APA (7th ed.) Citation

Dörfler, W., Harary, F., & Malle, G. COVERS OF DIGRAPHS.

Chicago Style (17th ed.) Citation

Dörfler, Willibald, Frank Harary, and Günther Malle. COVERS OF DIGRAPHS.

MLA (9th ed.) Citation

Dörfler, Willibald, et al. COVERS OF DIGRAPHS.