Adrian van Maanen
1946 / Adriaan Van Maanen, 1884-1946 / Frederick H. Seares / PASP 58 (1946) p. 89 [lien]
1972 / Adrian van Maanen and Internal Motions in Spiral Nebulae: a Historical Review / N. S. Hetherington / Quarterly Journal of the Royal Astronomical Society 13 (1972) p. 25 [lien]
1974 / Adriaan van Maanen on the Significance of Internal Motions in Spiral Nebulae / Norriss S. Hetherington / Journal for the History of Astronomy 5 (1974) p. 52 [lien]