@article{10_1090_S0894_0347_1989_1002631_0,
     author = {Hafner, James L. and McCurley, Kevin S.},
     title = {A rigorous subexponential algorithm for computation of class groups},
     journal = {Journal of the American Mathematical Society},
     pages = {837--850},
     publisher = {mathdoc},
     volume = {02},
     number = {4},
     year = {1989},
     doi = {10.1090/S0894-0347-1989-1002631-0},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-1989-1002631-0/}
}