MLA

Gernsheim, Helmut, and Alison Gernsheim. The History of Photography From the Camera Obscura to the Beginning of the Modern Era. Revised and enlarged ed. London: Thames & Hudson, 1969.

APA

Gernsheim, H., & Gernsheim, A. (1969). The history of photography from the camera obscura to the beginning of the modern era. Revised and enlarged ed. London: Thames & Hudson.

Chicago

Gernsheim, Helmut, and Alison Gernsheim. The History of Photography From the Camera Obscura to the Beginning of the Modern Era. Revised and enlarged ed. London: Thames & Hudson, 1969.