@article{MAN_1970__184_161927,
     author = {G. MAIBAUM},
     title = {\"Uber {Scharen} positiver {Operatoren.}},
     journal = {Mathematische Annalen},
     pages = {238--256},
     publisher = {mathdoc},
     volume = {184},
     year = {1970},
     zbl = {0176.10504},
     url = {http://geodesic.mathdoc.fr/item/MAN_1970__184_161927/}
}