@book{38697,
	author = {Takeuchi, Yu. and e-libro, Corp.},
	title = {Problemas elementales y soluciones difíciles},
	publisher = {Universidad del Valle,},
	year = {2005.},
	address = {Cali (Colombia) :},
	url = {https://elibro.net/ereader/politecnicointernacional/26287}
}