0120-6346
0120-6346
S0120-63462017000400187
10.22395/seec.v20n45a7
Ecuador
Ecuador
Ecuador
Ecuador
00
12
2017
00
12
2017
20
45
187
216
[
2012
4
3
3
38-43
]
[
2011
03-2011
03-2011
27
]
[
2005
25
25
5-35
]
[
1998
15
2
2
149-66
]
[
2001
30
109
109
691-722
]
[
2003
17
]
[
2007
249
]
[
1930
183
]
[
2008
36
6
6
1069-90
]
[
2012
]
[
2011
3
2
2
65-82
]
[
2017
8
14
14
185-200
]
[
2005
434
]
[
2001
1
1
1
27
]
[
2001
37
]
[
2012
9
991
]
[
1981
36
1
1
15-29
]
[
2010
719
]
[
2009
12
6
6
93-113
]
[
1998
53
2
2
635-72
]