@article{10_4064_fm_101_1_11_17,
     author = {Marcel Crabb\'e},
     title = {Ambiguity and stratification},
     journal = {Fundamenta Mathematicae},
     pages = {11--17},
     publisher = {mathdoc},
     volume = {101},
     number = {1},
     year = {1978},
     doi = {10.4064/fm-101-1-11-17},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-101-1-11-17/}
}