@Book{Petri1935,
author  = "Petri, Karl",
title   = "Über die Diskriminante ternärer Formen",
year    = "1935",
address = "München",
series  = "Sitzungsberichte",
volume  = "1935,19",
url     = "https://publikationen.badw.de/en/003395009",
}