tokens: We thank the anonymous referee for the comments and suggestions that improved this paper. We acknowledge Vladimir Avila-Reese, Xavier Hernandez, Manuel Peimbert and Liliana Hernández-Martínez, for helpful suggestions. LC thanks for the financial supports provided by CONACyT of México (grant 241732), by PAPIIT of México (IG110115, IA100815, IA101315) and by MINECO of Spain (AYA2010-16717). NA-V thanks for the financial support provided by Universidad Iberoamericana.
ner_tags: O O O O O O O O O O O O O O O O B-Person I-Person B-Person I-Person B-Person I-Person O B-Person I-Person O O O B-Person O O O O O O O B-Organization O B-Location B-Grant I-Grant O B-Organization O B-Location B-Grant B-Grant B-Grant O O B-Organization O B-Location B-Grant B-Person O O O O O O O B-Organization I-Organization