@incollection{JEDP_1995____A3_0,
     author = {Davies, E. Brian},
     title = {Heat kernel bounds for higher order elliptic operators},
     booktitle = {},
     series = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {3},
     pages = {1--11},
     publisher = {Ecole polytechnique},
     year = {1995},
     mrnumber = {96i:35020},
     zbl = {0994.58011},
     language = {en},
     url = {http://archive.numdam.org/item/JEDP_1995____A3_0/}
}