@Book{Tietze1956,
author  = "Tietze, Heinrich",
title   = "Bemerkungen zu Carathéodory's Einführung in Euler's Arbeiten über Variationsrechnung",
year    = "1956",
address = "München",
series  = "Sitzungsberichte",
volume  = "1955,1",
url     = "https://publikationen.badw.de/en/003383816",
}