@article{GT_2003_7_1_a2,
     author = {Ando, Matthew},
     title = {The sigma orientation for analytic circle-equivariant elliptic cohomology},
     journal = {Geometry & topology},
     pages = {91--153},
     publisher = {mathdoc},
     volume = {7},
     number = {1},
     year = {2003},
     doi = {10.2140/gt.2003.7.91},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/gt.2003.7.91/}
}