@Book{Lommel1882,
author  = "Lommel, Eugen von",
title   = "Theorie der elliptischen Doppelbrechung",
year    = "1882",
address = "München",
series  = "Sitzungsberichte",
volume  = "1882,2",
url     = "https://publikationen.badw.de/en/003394674",
}