@article{10_4153_CJM_1977_009_5,
     author = {Bernstein, Leon},
     title = {Gaining {Units} from {Units}},
     journal = {Canadian journal of mathematics},
     pages = {93--106},
     year = {1977},
     volume = {29},
     number = {1},
     doi = {10.4153/CJM-1977-009-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1977-009-5/}
}