Bunnell, Peter. 1993. Degrees of Guidance: Essays on Twentieth-Century American Photography. Cambridge University Press. Referenced from www.amazon.com: Degrees of Guidance: Essays on Twentieth-Century American Photography.

Bunnell, Peter. 2006. Inside the Photograph: Writings on Twentieth-Century Photography. Aperture Foundation. Referenced from aperture.org: Inside the Photograph: Writings on Twentieth-Century Photography.