no. 2
Morse indices of Yang-Mills connections over the unit sphere
Compositio Mathematica, Tome 98 (1995) no. 2, pp. 177-192. 
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     title = {Morse indices of {Yang-Mills} connections over the unit sphere},
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     publisher = {Kluwer Academic Publishers},
     volume = {98},
     number = {2},
     year = {1995},
     mrnumber = {1354267},
     zbl = {0836.53017},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1995__98_2_177_0/}
}
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Nayatani, Shin; Urakawa, Hajime. Morse indices of Yang-Mills connections over the unit sphere. Compositio Mathematica, Tome 98 (1995) no. 2, pp. 177-192. http://archive.numdam.org/item/CM_1995__98_2_177_0/

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