@article{10_4064_sm_27_3_325_335,
     author = {Israel Halperin},
     title = {Extension of the rank function},
     journal = {Studia Mathematica},
     pages = {325--335},
     publisher = {mathdoc},
     volume = {27},
     number = {3},
     year = {1966},
     doi = {10.4064/sm-27-3-325-335},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-27-3-325-335/}
}