@book{246541,
	author = {George, Darren. and Mallery, Paul.},
	title = {IBM statistics 21 step by step},
	publisher = {Pearson},
	year = {2014.},
	address = {Boston},
	edition = {Thirteenth edition.},
	note = {Earlier editions published by Allyn & Bacon as: SPSS for Windows step by step : a simple guide and reference.}
}