@book{401378,
title = {Z\'aklady teorie grupoid\r u a grup},
series = {GDML\_Books},
publisher = {Nakladatelstv\'\i\ \v ceskoslovensk\'e akademie v\v ed},
address = {Praha},
year = {1962},
mrnumber = {MR0155921},
language = {cs},
url = {http://dml.mathdoc.fr/item/401378}
}
Borůvka, Otakar. Základy teorie grupoidů a grup. GDML_Books (1962), http://gdmltest.u-ga.fr/item/401378/