@article{MZ_1994__216_4_174670,
     author = {Karl-Theodor Sturm},
     title = {Harnack's inequality for parabolic operators with singular low order terms.},
     journal = {Mathematische Zeitschrift},
     pages = {593--612},
     publisher = {mathdoc},
     volume = {216},
     number = {4},
     year = {1994},
     zbl = {0808.35044},
     url = {http://geodesic.mathdoc.fr/item/MZ_1994__216_4_174670/}
}