Autor:	Stover, Michael W., Myers, Shirley S., Miller, Richard L., Miller, Richard W., Pearon, Lynn A., Paulson, Dan, Burwell, Leonard, Reeves, Charles A., McAlear, Diane, Davis, Mary Jane
Zdroj:	The Arithmetic Teacher, 1972 Nov 01. 19(7), 585-599.
Databáze:	JSTOR Journals
Externí odkaz:	https://www.jstor.org/stable/41188112 Zobrazit plný text záznamu