@incollection{JEDP_1987____A9_0,
     author = {G\'erard, Patrick},
     title = {R\'egularit\'e de moyennes de solutions d'\'equations aux d\'eriv\'ees partielles},
     booktitle = {},
     series = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {9},
     pages = {1--8},
     publisher = {\'Ecole polytechnique},
     year = {1987},
     zbl = {0639.35010},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/JEDP_1987____A9_0/}
}