@article{10_4153_CJM_1975_097_5,
     author = {Varadarajan, K.},
     title = {Numerical {Invariants} in {Homotopical} {Algebra,} {I}},
     journal = {Canadian journal of mathematics},
     pages = {901--934},
     year = {1975},
     volume = {27},
     number = {4},
     doi = {10.4153/CJM-1975-097-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1975-097-5/}
}