Forde, G., Blumenfeld, E., & Citroen, P. R. (1993). Paul Citroen & Erwin Blumenfeld, 1919-1939: By Gerard Forde. Photographers' Gallery.
Chicago-Zitierstil (17. Ausg.)Forde, Gerard, Erwin Blumenfeld, 与 Paul Roelof Citroen. Paul Citroen & Erwin Blumenfeld, 1919-1939: By Gerard Forde. London: Photographers' Gallery, 1993.
MLA-Zitierstil (8. Ausg.)Forde, Gerard, et al. Paul Citroen & Erwin Blumenfeld, 1919-1939: By Gerard Forde. Photographers' Gallery, 1993.
警告：这些引文格式不一定是100％准确.