Rudolph and Minya Dührkoop :: The Dancer, Clotilde von Derp. (London Salon of Photography). Published by The Amateur Photographer & Photographic News, vol. LVIII, p. 264, September 22, 1913. | src and high resolution Musée Nicéphore Niépce | related post
Minya Diez-Dührkoop (Hamburg) :: Dancer Clotilde von Derp-Sacharoff. From Der Kunstlerische Tanz Unserer Zeit [The Artistic Dance of Our Time] p. 19. Published 1928. | src Marcus Bunyan (artblart)