no. 2
On the dual variety in characteristic 2
Compositio Mathematica, Tome 75 (1990) no. 2, pp. 129-134. 
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     author = {Ballico, Edoardo},
     title = {On the dual variety in characteristic 2},
     journal = {Compositio Mathematica},
     pages = {129--134},
     publisher = {Kluwer Academic Publishers},
     volume = {75},
     number = {2},
     year = {1990},
     mrnumber = {1065202},
     zbl = {0748.14018},
     language = {en},
     url = {http://www.numdam.org/item/CM_1990__75_2_129_0/}
}
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Ballico, Edoardo. On the dual variety in characteristic 2. Compositio Mathematica, Tome 75 (1990) no. 2, pp. 129-134. http://www.numdam.org/item/CM_1990__75_2_129_0/

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