Zapf, D., & Leymann, H. (1996). Foreword. [s.n.].
Chicago Style (17th ed.) CitationZapf, Dieter, and Heinz Leymann. Foreword. [S.l.]: [s.n.], 1996.
MLA (9th ed.) CitationZapf, Dieter, and Heinz Leymann. Foreword. [s.n.], 1996.
Warning: These citations may not always be 100% accurate.