1. Ancona, A.: On strong barriers and an inequality of Hardy for domains in R n . J. London Math. Soc. (2) 34(2), 274–290 (1986)
2. Andrews, G.E., Askey, R., Roy, R.: Special functions, volume 71 of Encyclopedia of Mathematics and its Applications. Cambridge University Press, Cambridge (1999)
3. Baras, P., Goldstein, J.A.: The heat equation with a singular potential. Trans. Amer. Math. Soc. 284(1), 121–139 (1984)
4. Beckner, W.: Pitt’s inequality and the fractional Laplacian: sharp error estimates. Forum Math. 24(1), 177–209 (2012)
5. Bogdan, K., Byczkowski, T., Kulczycki, T., Ryznar, M., Song, R., Vondraċek, Z.: Potential analysis of stable processes and its extensions, volume 1980 of Lecture Notes in Mathematics. Springer, Berlin (2009). Edited by Piotr Graczyk and Andrzej Stos