@article{10_4153_CJM_1999_022_5,
     author = {Burgess, W. D. and Saor{\'\i}n, Manuel},
     title = {Homological {Aspects} of {Semigroup} {Gradings} on {Rings} and {Algebras}},
     journal = {Canadian journal of mathematics},
     pages = {488--505},
     year = {1999},
     volume = {51},
     number = {3},
     doi = {10.4153/CJM-1999-022-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1999-022-5/}
}