@article{MET_1970__16_175456,
     author = {H. Vogt},
     title = {Zur {Definition} und {Sch\"atzung} von {Mittelwerten} f\"ur zuf\"allige {Variable} auf der {Sph\"are}},
     journal = {Metrika},
     pages = {206--235},
     publisher = {mathdoc},
     volume = {16},
     year = {1970},
     zbl = {0218.62028},
     url = {http://geodesic.mathdoc.fr/item/MET_1970__16_175456/}
}