@article{10_4064_sm_91_3_241_273,
     author = {Piotr Mormul},
     title = {Singularities of triples of vector fields on $R^{4}$: the focusing stratum},
     journal = {Studia Mathematica},
     pages = {241--273},
     publisher = {mathdoc},
     volume = {91},
     number = {3},
     year = {1988},
     doi = {10.4064/sm-91-3-241-273},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-91-3-241-273/}
}