@article{10_1090_S0894_0347_04_00449_7,
     author = {Oort, Frans},
     title = {Foliations in moduli spaces of abelian varieties},
     journal = {Journal of the American Mathematical Society},
     pages = {267--296},
     publisher = {mathdoc},
     volume = {17},
     number = {2},
     year = {2004},
     doi = {10.1090/S0894-0347-04-00449-7},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-04-00449-7/}
}