Positive quadratic differential forms : linearization, finite determinacy and versal unfolding
Annales de la Faculté des sciences de Toulouse : Mathématiques, Série 6, Tome 5 (1996) no. 4, pp. 661-690. 
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     author = {Gutierrez, Carlos and Gu{\'\i}\~nez, Victor},
     title = {Positive quadratic differential forms : linearization, finite determinacy and versal unfolding},
     journal = {Annales de la Facult\'e des sciences de Toulouse : Math\'ematiques},
     pages = {661--690},
     publisher = {Universit\'e Paul Sabatier},
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     volume = {Ser. 6, 5},
     number = {4},
     year = {1996},
     mrnumber = {1473078},
     zbl = {0882.58007},
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Gutierrez, Carlos; Guíñez, Victor. Positive quadratic differential forms : linearization, finite determinacy and versal unfolding. Annales de la Faculté des sciences de Toulouse : Mathématiques, Série 6, Tome 5 (1996) no. 4, pp. 661-690. http://archive.numdam.org/item/AFST_1996_6_5_4_661_0/

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