@Book{Tietze1947,
author  = "Tietze, Heinrich",
title   = "Eine Bemerkung zum Lehmerschen Problem",
year    = "1947",
address = "München",
series  = "Sitzungsberichte",
volume  = "1944,11",
url     = "https://publikationen.badw.de/en/003395641",
}