@Book{VossVolk1933,
author  = "Voss, Aurel and Volk, Otto [Sonst.]",
title   = "Über orthogonaloide Systeme",
year    = "1933",
address = "München",
series  = "Sitzungsberichte",
volume  = "1933,21",
url     = "https://publikationen.badw.de/de/003383421",
}