@article{PMIHES_1969__37__5_0,
     author = {Michael F. Atiyah and Isadore M. Singer},
     title = {Index theory for skew-adjoint {Fredholm} operators},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     pages = {5--26},
     year = {1969},
     publisher = {Institut des Hautes \'Etudes Scientifiques},
     volume = {37},
     doi = {10.1007/BF02684885},
     mrnumber = {285033},
     zbl = {0194.55503},
     language = {en},
     url = {https://pmihes.centre-mersenne.org/articles/10.1007/BF02684885/}
}