@Book{Koecher1990,
author  = "Koecher, Max",
title   = "Einige Bemerkungen zur Eulerschen Konstanten",
year    = "1990",
address = "München",
series  = "Sitzungsberichte",
volume  = "1989,2",
url     = "https://publikationen.badw.de/de/004271112",
}