@article{MAN_1989__283_1_164505,
     author = {Nicola Garofalo and Ermanno Lanconelli},
     title = {Asymptotic {Behavior} of {Fundamental} {Solutions} and {Potential} {Theory} of {Prabolic} {Operators} with {Variable} {Coeeficients.}},
     journal = {Mathematische Annalen},
     pages = {211--240},
     publisher = {mathdoc},
     volume = {283},
     number = {1},
     year = {1989},
     zbl = {0638.35003},
     url = {http://geodesic.mathdoc.fr/item/MAN_1989__283_1_164505/}
}