@article{CMUC_1988_29_2_a6,
     author = {Rotondaro, Giovanni},
     title = {An integral formula for closed surfaces and a generalization of $Hp$-theorem},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {253--254},
     year = {1988},
     volume = {29},
     number = {2},
     mrnumber = {957392},
     zbl = {0651.53042},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1988_29_2_a6/}
}