@incollection{AST_1981__89-90__213_0,
     author = {Lousberg, P.},
     title = {Backward parabolic equations},
     booktitle = {Analytic solutions of partial differential equations - Trento, 1981},
     series = {Ast\'erisque},
     pages = {213--221},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {89-90},
     year = {1981},
     mrnumber = {666410},
     zbl = {0502.35085},
     language = {en},
     url = {http://www.numdam.org/item/AST_1981__89-90__213_0/}
}