@Book{HeindlKöhler1969,
author  = "Heindl, Gerhard and Köhler, Günter",
title   = "Ein Monotoniekriterium",
year    = "1969",
address = "München",
series  = "Sitzungsberichte",
volume  = "1968,8",
url     = "https://publikationen.badw.de/en/003384229",
}