@article{ELMA_1989__44_3_141464,
     author = {B\'ela Bollob\'as},
     title = {An extension of the isoperimetric inequality on the sphere.},
     journal = {Elemente der Mathematik},
     pages = {121--124},
     publisher = {mathdoc},
     volume = {44},
     number = {3},
     year = {1989},
     zbl = {0714.52003},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1989__44_3_141464/}
}