no. 2
A new geometric invariant associated to the space of flat connections
Compositio Mathematica, Tome 73 (1990) no. 2, pp. 199-222. 
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     author = {Guruprasad, K. and Kumar, Shrawan},
     title = {A new geometric invariant associated to the space of flat connections},
     journal = {Compositio Mathematica},
     pages = {199--222},
     publisher = {Kluwer Academic Publishers},
     volume = {73},
     number = {2},
     year = {1990},
     zbl = {0698.53016},
     mrnumber = {1046738},
     language = {en},
     url = {http://www.numdam.org/item/CM_1990__73_2_199_0/}
}
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Guruprasad, K.; Kumar, Shrawan. A new geometric invariant associated to the space of flat connections. Compositio Mathematica, Tome 73 (1990) no. 2, pp. 199-222. http://www.numdam.org/item/CM_1990__73_2_199_0/

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