APA

Zelko H. P., . (1957). Successful conference and discussion techniques. New York: McGraw-Hill.

Chicago

Zelko Harold P, . 1957. Successful conference and discussion techniques. New York: McGraw-Hill.

Harvard

Zelko H. P., . (1957). Successful conference and discussion techniques. New York: McGraw-Hill.

MLA

Zelko Harold P, . Successful conference and discussion techniques. New York: McGraw-Hill. 1957.