@Book{Pfaff1883,
author  = "Pfaff, Friedrich",
title   = "Versuche die absolute Härte der Mineralien zu bestimmen",
year    = "1883",
address = "München",
series  = "Sitzungsberichte",
volume  = "1883,5",
url     = "https://publikationen.badw.de/en/003394568",
}