Crookes, William; Simpson, G. Wharton (1860). "Dictionary of Photography". The Photographic News. 3–4: 787. Archived from the original on 30 June 2023. Retrieved 30 June 2023.
Crookes, William; Simpson, G. Wharton (1860). "Dictionary of Photography". The Photographic News. 3–4: 787. Archived from the original on 30 June 2023. Retrieved 30 June 2023.