@article{10_4064_fm_113_1_9_19,
     author = {Zygmunt Ratajczyk},
     title = {A characterization of expandability of models for {ZF} to models for {KM}},
     journal = {Fundamenta Mathematicae},
     pages = {9--19},
     publisher = {mathdoc},
     volume = {113},
     number = {1},
     year = {1981},
     doi = {10.4064/fm-113-1-9-19},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-113-1-9-19/}
}