Kolmogorov's forward, basic results
Non-elliptic regularity results
Preliminary elliptic regularity results
Nash theory
Localization
On a manifold
Subelliptic estimates and Hörmander's theorem.
Partial differential equations for probabalists [sic] by Daniel W. Stroock. ISBN 9780521886512. Published by Cambridge University Press in 2008. Publication and catalogue information, links to buy online and reader comments.