APA

Hammock R. C., Owings R. S., . (1955). Supervising instruction in secondary schools. New York: McGraw-Hill.

Chicago

Hammock Robert C, Owings Ralph S, . 1955. Supervising instruction in secondary schools. New York: McGraw-Hill.

Harvard

Hammock R. C., Owings R. S., . (1955). Supervising instruction in secondary schools. New York: McGraw-Hill.

MLA

Hammock Robert C, Owings Ralph S, . Supervising instruction in secondary schools. New York: McGraw-Hill. 1955.