Gaya APA

Swanson, C, P., Underhil, B. (NULL). Teaching Elemantary School Mathematics . Columbus:: Columbus: A Bell & Howell Company; 1981.

Gaya MLA

Swanson, Carl, P.., Underhil, Bob. "Teaching Elemantary School Mathematics". Columbus:: Columbus: A Bell & Howell Company; 1981, NULL. Text.