@article{MM2_1977__21_154454,
     author = {J\"urgen Lehn and Albert Ascherl},
     title = {Two {Principles} for {Extending} {Probability} {Measures.}},
     journal = {Manuscripta mathematica},
     pages = {43--50},
     publisher = {mathdoc},
     volume = {21},
     year = {1977},
     zbl = {0368.60005},
     url = {http://geodesic.mathdoc.fr/item/MM2_1977__21_154454/}
}