@article{10_4153_CJM_1971_061_0,
     author = {Wright, Michael J.},
     title = {On the {Number} of {Prolongations} of a {Finite} {Rank} {Valuation}},
     journal = {Canadian journal of mathematics},
     pages = {553--556},
     year = {1971},
     volume = {23},
     number = {3},
     doi = {10.4153/CJM-1971-061-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1971-061-0/}
}