@book{PPN516792814, title = {Elemente der Quaternionen Bd. 1}, series = {GDML\_Books}, year = {1882}, zbl = {16.0616.02}, language = {ger}, url = {http://dml.mathdoc.fr/item/PPN516792814} }
(éd.). Elemente der Quaternionen Bd. 1. GDML_Books (1882), http://gdmltest.u-ga.fr/item/PPN516792814/