@article{AM_1999_150_1_a8,
     author = {Mikhail V. Safonov and Yu Yuan},
     title = {Doubling properties for second order parabolic equations},
     journal = {Annals of mathematics},
     publisher = {mathdoc},
     volume = {150},
     number = {1},
     year = {1999},
     url = {http://geodesic.mathdoc.fr/item/AM_1999_150_1_a8/}
}