@Book{Volk(1922),
author  = "Volk, Otto",
title   = "Über die Reihe [Unendlichkeitszeichen] [Summenzeichen]| n=0 Pn(x)",
year    = "(1922)",
address = "München",
series  = "Sitzungsberichte",
volume  = "1922,4",
url     = "https://publikationen.badw.de/en/021034976",
}