APA

Risk T. M., . (1947). Principles and practices of teaching in secondary schools. New York: American Book Co.

Chicago

Risk Thomas M, . 1947. Principles and practices of teaching in secondary schools. New York: American Book Co.

Harvard

Risk T. M., . (1947). Principles and practices of teaching in secondary schools. New York: American Book Co.

MLA

Risk Thomas M, . Principles and practices of teaching in secondary schools. New York: American Book Co. 1947.