@article{CMH_1970__45_139456,
     author = {Heinz G. Helfenstein},
     title = {Analytic {Maps} {Between} {Tori.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {530--539},
     publisher = {mathdoc},
     volume = {45},
     year = {1970},
     zbl = {0203.54302},
     url = {http://geodesic.mathdoc.fr/item/CMH_1970__45_139456/}
}