1. Aizenman, N., Simon, B.: Brownian motion and Harnack inequality for Schrődinger operators, Comm. Pure Appl. Math. 35 (1982), 209–273.
2. Chung, K.L.: On stopped Feynman-Kac functionals, Séminaire de Probabilités XIV, 1978/79, Lecture Notes in Mathematics No. 784, Springer-Verlag.
3. Chung, K.L., Rao, K.M.: Feynman-Kac functional and Schrődinger equation, Seminar on Stochastic Processes 1, 1–29, Birkhäuser 1981.
4. Chung, K.L.: Conditional gauges, Seminar on Stochastic Processes 3, 1983.
5. Falkner, N.: Feynman-Kac functionals and positive solutions of ½Δu+qu=0, Z. Wahrsch. Verw. Gebiete 65 (1983), 19–33.