APA

Franklin P., . (19). The four color problem. New York: Scripta Mathematica,Yeshiva College.

Chicago

Franklin Philip, . 19. The four color problem. New York: Scripta Mathematica,Yeshiva College.

Harvard

Franklin P., . (19). The four color problem. New York: Scripta Mathematica,Yeshiva College.

MLA

Franklin Philip, . The four color problem. New York: Scripta Mathematica,Yeshiva College. 19.