@Book{Wilkens1954,
author  = "Wilkens, Alexander",
title   = "Der Hodograph der Gravitation zweier Massenpunkte",
year    = "1954",
address = "München",
series  = "Sitzungsberichte",
volume  = "1953,13",
url     = "https://publikationen.badw.de/de/003383748",
}