@article{FORUM_1996__8_3_141762,
     author = {Walter Hoh and Niels Jacob},
     title = {Upper bounds and conservativeness for semigroups associated with a class of {Dirichlet} forms generated by pseudo differential operators.},
     journal = {Forum mathematicum},
     pages = {107--120},
     publisher = {mathdoc},
     volume = {8},
     number = {3},
     year = {1996},
     zbl = {0849.31014},
     url = {http://geodesic.mathdoc.fr/item/FORUM_1996__8_3_141762/}
}