<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0123-7799</journal-id>
<journal-title><![CDATA[TecnoLógicas]]></journal-title>
<abbrev-journal-title><![CDATA[TecnoL.]]></abbrev-journal-title>
<issn>0123-7799</issn>
<publisher>
<publisher-name><![CDATA[Instituto Tecnológico Metropolitano - ITM]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0123-77992022000300201</article-id>
<article-id pub-id-type="doi">10.22430/22565337.2343</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Characterization of Preliminary Breakdown Pulse Trains in Negative Cloud-To-Ground Flashes Recorded during A Rainy Season in The Bogota Savannah, Colombia]]></article-title>
<article-title xml:lang="es"><![CDATA[Caracterización de trenes de descargas preliminares en rayos nube a tierra negativos registrados durante una temporada de lluvias en la Sabana de Bogotá, Colombia]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Granados]]></surname>
<given-names><![CDATA[Camilo A.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rojas]]></surname>
<given-names><![CDATA[Herbert E.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Román]]></surname>
<given-names><![CDATA[Francisco J.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Nacional de Colombia  ]]></institution>
<addr-line><![CDATA[Bogotá ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Distrital Francisco José de Caldas  ]]></institution>
<addr-line><![CDATA[Bogotá ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad Nacional de Colombia  ]]></institution>
<addr-line><![CDATA[Bogotá ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2022</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2022</year>
</pub-date>
<volume>25</volume>
<numero>55</numero>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0123-77992022000300201&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0123-77992022000300201&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0123-77992022000300201&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Lightning-generated electric field measurement is used to characterize cloud-to-ground (CG) flashes. Prior to the first return stroke (FRS), these signals sometimes exhibit a pulse train, known as preliminary breakdown pulses (PBP), whose study provides information about the first event that originate the breakdown process inside the cloud. Considering that characteristics of PBPs may change according to geographical conditions, in this work, six parameters (temporal and magnitude) associated with 69 trains identified in negative CG flashes that occurred in the Bogota savannah, Colombia were analyzed. The signatures were recorded in 2017 using a fast response antenna (10 MHz bandwidth), a 100 ns sampling time and a window of 500 ms. Among the most relevant results, it was found that the train duration (T  PBP ) varied from 0.5 ms up to 5.2 ms with arithmetic mean (AM) of 1.74 ms, while the time interval between the peak of the train and the FRS (PBP-FRS) had an AM and a geometric mean (GM) of 35.7 ms and 10.2 ms, respectively. On the other hand, the ratio between the peak value of the PBP and its FRS (PBP  MAX /FRS  M ) exhibited an AM of 0.7 and a GM of 0.56. It was concluded that PBP train starts with low amplitude pulses, later increases its magnitude in the central region and decreases at the end. Furthermore, bipolar pulses with similar polarity to that of the FRS were identified at the beginning and in the middle of the train, while unipolar pulses were observed at the end of the signatures.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen La medición del campo eléctrico generado por rayos es comúnmente usada para caracterizar rayos nube-tierra (CG). Previo a la primera descarga de retorno (FRS), estas señales exhiben algunas veces un tren de pulsos conocido como pulsos de descargas preliminares (PBP), cuyo estudio proporciona información sobre el primer evento que origina el proceso de descarga dentro de la nube. Considerando que las características de los PBP pueden cambiar de acuerdo con las condiciones geográficas, en este trabajo se analizaron seis parámetros (temporales y de magnitud) asociados a 69 trenes identificados en rayos CG negativos ocurridos en la Sabana de Bogotá, Colombia. Las señales se registraron en 2017 usando una antena de respuesta rápida (ancho de banda de 10 MHz), un tiempo de muestreo de 100 ns y una ventana de 500 ms. Dentro de los resultados más relevantes se encontró que la duración del tren (T  PBP ) varió entre 0.5 ms y 5.2 ms con una media aritmética (AM) de 1.74 ms, mientras el tiempo entre el pico del tren y el FRS (PBP-FRS) tuvo una AM y una media geométrica (GM) de 35.7 ms y 10.2 ms, respectivamente. Por su parte, la relación entre el pico del PBP y su FRS (PBP  MAX /FRS  M ) exhibió una AM de 0.7 y una GM de 0.56. Se concluye que el tren comienza con pulsos de baja amplitud, aumenta su magnitud en la región central y disminuye al final. Adicionalmente, se identificaron pulsos bipolares con polaridad similar a la FRS al principio y en la mitad del tren, mientras pulsos unipolares fueron observados al final de las señales.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Pulse amplitude]]></kwd>
<kwd lng="en"><![CDATA[return stroke]]></kwd>
<kwd lng="en"><![CDATA[electric field measurement]]></kwd>
<kwd lng="en"><![CDATA[preliminary breakdown pulses]]></kwd>
<kwd lng="en"><![CDATA[cloud-to-ground lightning]]></kwd>
<kwd lng="es"><![CDATA[Amplitud del pulso]]></kwd>
<kwd lng="es"><![CDATA[descarga de retorno]]></kwd>
<kwd lng="es"><![CDATA[medición del campo eléctrico]]></kwd>
<kwd lng="es"><![CDATA[pulsos de descargas preliminares]]></kwd>
<kwd lng="es"><![CDATA[rayos nube-tierra]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<label>[1]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Salimi]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Mehranzamir]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
<name>
<surname><![CDATA[Abdul-Malek]]></surname>
<given-names><![CDATA[Z.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Statistical Analysis of Lightning Electric Field Measured Under Equatorial Region Condition]]></article-title>
<source><![CDATA[Procedia Technology]]></source>
<year>2013</year>
<volume>11</volume>
<page-range>525-31</page-range></nlm-citation>
</ref>
<ref id="B2">
<label>[2]</label><nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Uman]]></surname>
<given-names><![CDATA[M. A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Lightning]]></source>
<year>2012</year>
<publisher-loc><![CDATA[New York, USA ]]></publisher-loc>
</nlm-citation>
</ref>
<ref id="B3">
<label>[3]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Schumann]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
<name>
<surname><![CDATA[Saba]]></surname>
<given-names><![CDATA[M. M. F.]]></given-names>
</name>
<name>
<surname><![CDATA[da Silva]]></surname>
<given-names><![CDATA[R. B. G.]]></given-names>
</name>
<name>
<surname><![CDATA[Schulz]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Electric fields changes produced by positives cloud-to-ground lightning flashes]]></article-title>
<source><![CDATA[J. Atmos. Solar-Terrestrial Phys]]></source>
<year>2013</year>
<volume>92</volume>
<page-range>37-42</page-range></nlm-citation>
</ref>
<ref id="B4">
<label>[4]</label><nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rakov]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
</person-group>
<source><![CDATA[Characterization of lighting electromagnetic fields and their modeling]]></source>
<year></year>
<conf-name><![CDATA[ The International Conference on Electrical Engineering, 6]]></conf-name>
<conf-date>May 2008</conf-date>
<conf-loc> </conf-loc>
<page-range>1-31</page-range></nlm-citation>
</ref>
<ref id="B5">
<label>[5]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rakov]]></surname>
<given-names><![CDATA[V. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Uman]]></surname>
<given-names><![CDATA[M. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Review and evaluation of lightning return stroke models including some aspects of their application]]></article-title>
<source><![CDATA[IEEE Trans. Electromagn. Compat.]]></source>
<year>1998</year>
<volume>40</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>403-26</page-range></nlm-citation>
</ref>
<ref id="B6">
<label>[6]</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Hoole]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Hoole]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Lightning Engineering: Physics, Computer-based Test-bed, Protection of Ground and Airborne Systems]]></source>
<year>2022</year>
<edition>1</edition>
<publisher-loc><![CDATA[Cham ]]></publisher-loc>
<publisher-name><![CDATA[Springer International Publishing]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B7">
<label>[7]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Herrera]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Younes]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
<name>
<surname><![CDATA[Porras]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Cloud-to-ground lightning activity in Colombia: A 14-year study using lightning location system data]]></article-title>
<source><![CDATA[Atmos. Res.]]></source>
<year>2018</year>
<volume>203</volume>
<page-range>164-74</page-range></nlm-citation>
</ref>
<ref id="B8">
<label>[8]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rojas]]></surname>
<given-names><![CDATA[H. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Cruz]]></surname>
<given-names><![CDATA[A. S.]]></given-names>
</name>
<name>
<surname><![CDATA[Cortes]]></surname>
<given-names><![CDATA[C. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Characteristics of electric field waveforms produced by negative return strokes in Colombia and their comparison with other regions]]></article-title>
<source><![CDATA[J. Atmos. Solar-Terrestrial Phys]]></source>
<year>2022</year>
<volume>227</volume>
<page-range>105809</page-range></nlm-citation>
</ref>
<ref id="B9">
<label>[9]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rojas]]></surname>
<given-names><![CDATA[H. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Rojas]]></surname>
<given-names><![CDATA[H. D.]]></given-names>
</name>
<name>
<surname><![CDATA[Cortes]]></surname>
<given-names><![CDATA[C. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Statistical analysis of negative cloud-to-ground lightning characteristics in Bogota, Colombia based on electric field measurements]]></article-title>
<source><![CDATA[J. Atmos. Solar-Terrestrial Phys]]></source>
<year>2022</year>
<volume>227</volume>
<page-range>105798</page-range></nlm-citation>
</ref>
<ref id="B10">
<label>[10]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Clarence]]></surname>
<given-names><![CDATA[N. D.]]></given-names>
</name>
<name>
<surname><![CDATA[Malan]]></surname>
<given-names><![CDATA[D. J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Preliminary discharge processes in lightning flashes to ground]]></article-title>
<source><![CDATA[Q. J. R. Meteorol. Soc.]]></source>
<year>1957</year>
<volume>83</volume>
<numero>356</numero>
<issue>356</issue>
<page-range>161-72</page-range></nlm-citation>
</ref>
<ref id="B11">
<label>[11]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Azlinda Ahmad]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[The first electric field pulse of cloud and cloud-to-ground lightning discharges]]></article-title>
<source><![CDATA[J. Atmos. Solar-Terrestrial Phys]]></source>
<year>2010</year>
<volume>72</volume>
<numero>2-3</numero>
<issue>2-3</issue>
<page-range>143-50</page-range></nlm-citation>
</ref>
<ref id="B12">
<label>[12]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Baharudin]]></surname>
<given-names><![CDATA[Z. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Ahmad]]></surname>
<given-names><![CDATA[N. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Fernando]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Cooray]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
<name>
<surname><![CDATA[Mäkelä]]></surname>
<given-names><![CDATA[J. S.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Comparative study on preliminary breakdown pulse trains observed in Johor, Malaysia and Florida, USA]]></article-title>
<source><![CDATA[Atmos. Res.]]></source>
<year>2012</year>
<volume>117</volume>
<page-range>111-21</page-range></nlm-citation>
</ref>
<ref id="B13">
<label>[13]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Mäkelä]]></surname>
<given-names><![CDATA[J. S.]]></given-names>
</name>
<name>
<surname><![CDATA[Porjo]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
<name>
<surname><![CDATA[Mäkelä]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Tuomi]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
<name>
<surname><![CDATA[Cooray]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Properties of preliminary breakdown processes in Scandinavian lightning]]></article-title>
<source><![CDATA[J. Atmos. Solar-Terrestrial Phys]]></source>
<year>2008</year>
<volume>70</volume>
<numero>16</numero>
<issue>16</issue>
<page-range>2041-52</page-range></nlm-citation>
</ref>
<ref id="B14">
<label>[14]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gomes]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
<name>
<surname><![CDATA[Cooray]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
<name>
<surname><![CDATA[Jayaratne]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Comparison of preliminary breakdown pulses observed in Sweden and in Sri Lanka]]></article-title>
<source><![CDATA[J. Atmos. Solar-Terrestrial Phys]]></source>
<year>1998</year>
<volume>60</volume>
<numero>10</numero>
<issue>10</issue>
<page-range>975-9</page-range></nlm-citation>
</ref>
<ref id="B15">
<label>[15]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cooray]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
<name>
<surname><![CDATA[Jayaratne]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[What directs a lightning flash towards ground?]]></article-title>
<source><![CDATA[Sri Lankan J. Phys.]]></source>
<year>2000</year>
<volume>1</volume>
<page-range>1-10</page-range></nlm-citation>
</ref>
<ref id="B16">
<label>[16]</label><nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Miranda]]></surname>
<given-names><![CDATA[F. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Pinto Jr]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<name>
<surname><![CDATA[Saba]]></surname>
<given-names><![CDATA[M. M. F.]]></given-names>
</name>
</person-group>
<source><![CDATA[Occurrence of characteristic pulses in positive ground lightning in Brazil]]></source>
<year></year>
<conf-name><![CDATA[ 19th International Lightning Detection Conference]]></conf-name>
<conf-date>Apr. 2006</conf-date>
<conf-loc> </conf-loc>
<page-range>1-6</page-range></nlm-citation>
</ref>
<ref id="B17">
<label>[17]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wu]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Preliminary breakdown pulses of cloud-to-ground lightning in winter thunderstorms in Japan]]></article-title>
<source><![CDATA[J Atmos Sol Terr Phys]]></source>
<year>2013</year>
<volume>102</volume>
<page-range>91-8</page-range></nlm-citation>
</ref>
<ref id="B18">
<label>[18]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zhang]]></surname>
<given-names><![CDATA[Y.]]></given-names>
</name>
<name>
<surname><![CDATA[Zhang]]></surname>
<given-names><![CDATA[Y. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Lu]]></surname>
<given-names><![CDATA[W. T.]]></given-names>
</name>
<name>
<surname><![CDATA[Zheng]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Analysis and comparison of initial breakdown pulses for positive cloud-to-ground flashes observed in Beijing and Guangzhou]]></article-title>
<source><![CDATA[Atmos. Res.]]></source>
<year>2013</year>
<volume>129-130</volume>
<page-range>34-41</page-range></nlm-citation>
</ref>
<ref id="B19">
<label>[19]</label><nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rojas]]></surname>
<given-names><![CDATA[H. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Rivera]]></surname>
<given-names><![CDATA[C. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Chaves]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Cortés]]></surname>
<given-names><![CDATA[C. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Román]]></surname>
<given-names><![CDATA[F. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Fernando]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[New circuit for the measurement of lightning generated electric fields]]></source>
<year></year>
<conf-name><![CDATA[ 2017 International Symposium on Lightning Protection (XIV SIPDA)]]></conf-name>
<conf-date>Oct. 2017</conf-date>
<conf-loc> </conf-loc>
<page-range>188-94</page-range></nlm-citation>
</ref>
<ref id="B20">
<label>[20]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Johari]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Cooray]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
<name>
<surname><![CDATA[Rahman]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Hettiarachchi]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Ismail]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Characteristics of Preliminary Breakdown Pulses in Positive Ground Flashes during Summer Thunderstorms in Sweden]]></article-title>
<source><![CDATA[Atmosphere]]></source>
<year>2016</year>
<volume>7</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>1-18</page-range></nlm-citation>
</ref>
<ref id="B21">
<label>[21]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Nag]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Rakov]]></surname>
<given-names><![CDATA[V. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Pulse trains that are characteristic of preliminary breakdown in cloud-to-ground lightning but are not followed by return stroke pulses]]></article-title>
<source><![CDATA[J. Geophys. Res. Atmos]]></source>
<year>2008</year>
<volume>113</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>1-12</page-range></nlm-citation>
</ref>
<ref id="B22">
<label>[22]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Nag]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Rakov]]></surname>
<given-names><![CDATA[V. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Electric Field Pulse Trains Occurring Prior to the First Stroke in Negative Cloud-to-Ground Lightning]]></article-title>
<source><![CDATA[IEEE Trans. Electromagn. Compat.]]></source>
<year>2009</year>
<volume>51</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>147-50</page-range></nlm-citation>
</ref>
<ref id="B23">
<label>[23]</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rakov]]></surname>
<given-names><![CDATA[V. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Uman]]></surname>
<given-names><![CDATA[M. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Hoffman]]></surname>
<given-names><![CDATA[G. R.]]></given-names>
</name>
<name>
<surname><![CDATA[Masters]]></surname>
<given-names><![CDATA[M. W.]]></given-names>
</name>
<name>
<surname><![CDATA[Brook]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Burst of pulses in lightning electromagnetic radiation: observations and implications for lightning test standards]]></article-title>
<source><![CDATA[IEEE Trans. Electromagn. Compat.]]></source>
<year>1996</year>
<volume>38</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>156-64</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
