@Book{Seeliger1921,
author  = "Seeliger, Hugo von",
title   = "Untersuchungen über das Sternsystem",
year    = "1921",
address = "München",
series  = "Sitzungsberichte",
volume  = "1920,7",
url     = "https://publikationen.badw.de/de/003395457",
}