@incollection{AST_1984__119-120__191_0,
     author = {Robba, Philippe},
     title = {Index of $p$-adic differential operators {III.} {Application} to twisted exponential sums},
     booktitle = {Cohomologie $p$-adique},
     series = {Ast\'erisque},
     pages = {191--266},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {119-120},
     year = {1984},
     mrnumber = {773094},
     zbl = {0548.12015},
     language = {en},
     url = {http://www.numdam.org/item/AST_1984__119-120__191_0/}
}