APA

Ljungren R. G., American Management Association, . (1989). The business-to-business direct marketing handbook. New York: American Management Association.

Chicago

Ljungren Roy G, American Management Association, . 1989. The business-to-business direct marketing handbook. New York: American Management Association.

Harvard

Ljungren R. G., American Management Association, . (1989). The business-to-business direct marketing handbook. New York: American Management Association.

MLA

Ljungren Roy G, American Management Association, . The business-to-business direct marketing handbook. New York: American Management Association. 1989.