@article{10_4153_CJM_1967_024_5,
     author = {Barrar, Richard B.},
     title = {Proof of the {Fixed} {Point} {Theorems} of {Poincar\'e} and {Birkhoff}},
     journal = {Canadian journal of mathematics},
     pages = {333--343},
     year = {1967},
     volume = {19},
     number = {1},
     doi = {10.4153/CJM-1967-024-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1967-024-5/}
}