APA

Roberts R. W., NORTHEN HELEN, . (1976). Theories of social work with groups. New York: Columbia University Press.

Chicago

Roberts Robert W, NORTHEN HELEN, . 1976. Theories of social work with groups. New York: Columbia University Press.

Harvard

Roberts R. W., NORTHEN HELEN, . (1976). Theories of social work with groups. New York: Columbia University Press.

MLA

Roberts Robert W, NORTHEN HELEN, . Theories of social work with groups. New York: Columbia University Press. 1976.