@article{10_4064_ap_62_3_265_281,
     author = {Grzegorz \'Swirszcz},
     title = {Versal deformations of $D_q$-invariant 2-parameter families of planar vector fields},
     journal = {Annales Polonici Mathematici},
     pages = {265--281},
     publisher = {mathdoc},
     volume = {62},
     number = {3},
     year = {1995},
     doi = {10.4064/ap-62-3-265-281},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-62-3-265-281/}
}