@article{PORMA_1963__22_3_114902,
     author = {Hsiang, Fu Cheng},
     title = {On a theorem of {Burkill-Petersen}},
     journal = {Portugaliae mathematica},
     pages = {137--141},
     publisher = {mathdoc},
     volume = {22},
     number = {3},
     year = {1963},
     mrnumber = {0216199},
     zbl = {0133.01202},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1963__22_3_114902/}
}