APA

Saaty T. L., Kainen P. C., . (1977). The four-color problem. New York: McGraw-Hill International Book Company.

Chicago

Saaty Thomas L, Kainen Paul C, . 1977. The four-color problem. New York: McGraw-Hill International Book Company.

Harvard

Saaty T. L., Kainen P. C., . (1977). The four-color problem. New York: McGraw-Hill International Book Company.

MLA

Saaty Thomas L, Kainen Paul C, . The four-color problem. New York: McGraw-Hill International Book Company. 1977.