@BOOK {
	EDITOR = "Ulrich Kohlenbach and Pablo Barcel{\'o} and Ruy de Queiroz",
	TITLE = "Proceedings of the 21th Workshop on Logic, Language, Information, and Computation (WOLLIC)",
	YEAR = "2014",
	ADDRESS = "Valpara{\'{\i}}so, Chile",
	PUBLISHER = "Springer",
	SERIES ="Lecture Notes in Computer Science",
	}