Gaya APA

Green, G, F., Swanson, C, P. (1974). Elementary school mathematics activities and materials . Massachusetts: Massachusetts: D.C. Heath and Co.; 1974..

Gaya MLA

Green, George, F.., Swanson, Carl, P.. "Elementary school mathematics activities and materials". Massachusetts: Massachusetts: D.C. Heath and Co.; 1974., 1974. Text.