@article{10_4064_cm_42_1_279_284,
     author = {Z. Lipecki and D. Plachky and W. Thomsen},
     title = {Extensions of positive operators and extreme points. {I}},
     journal = {Colloquium Mathematicum},
     pages = {279--284},
     publisher = {mathdoc},
     volume = {42},
     number = {1},
     year = {1979},
     doi = {10.4064/cm-42-1-279-284},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-42-1-279-284/}
}