@article{MZ_1933__37_168485,
     author = {Oskar Perron},
     title = {Diophantische {Approximationen} in imagin\"aren quadratischen {Zahlk\"orpern,} insbesondere im {K\"orper} {K} (i...2).},
     journal = {Mathematische Zeitschrift},
     pages = {749--767},
     year = {1933},
     volume = {37},
     zbl = {0007.33804},
     url = {http://geodesic.mathdoc.fr/item/MZ_1933__37_168485/}
}