APA

Drucker P. F., . (1980). Managing in turbulent times. New York: Harper & Row.

Chicago

Drucker Peter Ferdinand, . 1980. Managing in turbulent times. New York: Harper & Row.

Harvard

Drucker P. F., . (1980). Managing in turbulent times. New York: Harper & Row.

MLA

Drucker Peter Ferdinand, . Managing in turbulent times. New York: Harper & Row. 1980.