Children discover arithmetic; an introduction to structural arithmetic.

MLA

Stern, Catherine and Gotham Book Mart Collection (University of Pennsylvania). Children discover arithmetic; an introduction to structural arithmetic. [First edition]. New York : Harper, [1949]

APA

Stern, C. & Gotham Book Mart Collection (University of Pennsylvania). (1949). Children discover arithmetic; an introduction to structural arithmetic. [First edition]. New York : Harper.

Chicago

Stern, Catherine and Gotham Book Mart Collection (University of Pennsylvania). Children discover arithmetic; an introduction to structural arithmetic. [First edition]. New York : Harper, [1949]