@article{10_4153_CJM_1969_164_7,
     author = {Douglas, A. J.},
     title = {Generalized {Casimir} {Operators}},
     journal = {Canadian journal of mathematics},
     pages = {1496--1505},
     year = {1969},
     volume = {21},
     number = {1},
     doi = {10.4153/CJM-1969-164-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1969-164-7/}
}