@article{IM_1986__85_143364,
     author = {E. Kani},
     title = {Bounds on the number of non-rational subfields of a function field.},
     journal = {Inventiones mathematicae},
     pages = {185--198},
     publisher = {mathdoc},
     volume = {85},
     year = {1986},
     zbl = {0615.12017},
     url = {http://geodesic.mathdoc.fr/item/IM_1986__85_143364/}
}