@article{MS2_1978__42_166576,
     author = {C.L. Childress and G.L. Csordas},
     title = {The {Iversen} theorem in a polydisc.},
     journal = {Mathematica Scandinavica},
     pages = {64--70},
     publisher = {mathdoc},
     volume = {42},
     year = {1978},
     zbl = {0399.32004},
     url = {http://geodesic.mathdoc.fr/item/MS2_1978__42_166576/}
}