APA (7th ed.) Citation

Harper Collins, Aas, G., Riedmiller, A., & Walters, M. (1994). Trees of Britain and Europe. Harper Collins.

Chicago Style (17th ed.) Citation

Harper Collins, G. Aas, A. Riedmiller, and Martin Walters. Trees of Britain and Europe. London: Harper Collins, 1994.

MLA (8th ed.) Citation

Harper Collins, et al. Trees of Britain and Europe. Harper Collins, 1994.