@article{CMH_1975__50_139607,
     author = {Samuel S.H. Young},
     title = {The {Hurwitz} {Matrix} {Equations} and {Multifour} {Groups.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {45--58},
     publisher = {mathdoc},
     volume = {50},
     year = {1975},
     zbl = {0305.15006},
     url = {http://geodesic.mathdoc.fr/item/CMH_1975__50_139607/}
}