1. Harmonic Analysis and the Theory of Probability
2. W. Feller, An introduction to probability theory and its applications, Vol. 1, 2d ed., New York, 1957.
3. On the intrinsic form for second order differential operators;Feller, William;Illinois J. Math.,1958
4. Some theorems concerning Brownian motion;Hunt, G. A.;Trans. Amer. Math. Soc.,1956