Speaking of which...

MLA

Andreasen, Kasper, Louis Lüthi, and Richard Males. Speaking of Which... [Liège]: [Comptoir], 2007.

APA

Andreasen, K., Lüthi, L., & Males, R. (2007). Speaking of which... [Liège]: [Comptoir].

Chicago

Andreasen, Kasper, Louis Lüthi, and Richard Males. Speaking of Which.... [Liège]: [Comptoir], 2007.