Forde, G., Blumenfeld, E., & Citroen, P. R. (1993). Paul Citroen & Erwin Blumenfeld, 1919-1939: By Gerard Forde. Photographers' Gallery.
Chicago Style (17th ed.) CitationForde, Gerard, Erwin Blumenfeld, and Paul Roelof Citroen. Paul Citroen & Erwin Blumenfeld, 1919-1939: By Gerard Forde. London: Photographers' Gallery, 1993.
MLA (8th ed.) CitationForde, Gerard, et al. Paul Citroen & Erwin Blumenfeld, 1919-1939: By Gerard Forde. Photographers' Gallery, 1993.
Warning: These citations may not always be 100% accurate.