A handbook of varieties of English :
a multimedia reference tool, two volumes plus CD-ROM /
edited by Bernd Kortmann and Edgar W. Schneider ; together with Kate Burridge ... [et al.]

APA Citation

Kortmann, B., Schneider, E. W. (Edgar Werner)., Walter de Gruyter & Co. (2004). A handbook of varieties of English: a multimedia reference tool, two volumes plus CD-ROM. Berlin: Mouton de Gruyter.

MLA Citation

Kortmann, Bernd, 1960-, Edgar W. (Edgar Werner) Schneider, and Walter de Gruyter & Co. A Handbook of Varieties of English: a Multimedia Reference Tool, Two Volumes Plus CD-ROM. Berlin: Mouton de Gruyter, 2004.

Warning: These citations may not always be complete (especially for serials).