Heber Curtis

1942 / Heber Doust Curtis, 1872-1942 / Robert R. McMath / PASP 54 (1942) p. 69 [lien]
1976 / Ritchey, Curtis and the Discovery of Novae in Spiral Nebulae / M. A. Hoskin / Journal for the History of Astronomy 7 (1976) p. 47 [lien]