Courant, R. and Gilbert, D. (1962). Methods of Mathematical Physics, Vol 2, Partial Differential Equations. Interscience, New York.
John, F. (1955). Plane Waves and Spherical Means Applied to Partial Differential Equations. Interscience, New York.
Kolesnik, A. D. and Orsingher, E. (2005). A planar random motion with an infinite number of directions controlled by the damped wave equation. J. Appl. Prob.
Masoliver, J., Porrá, J. M. and Weiss, G. H. (1993). Some two and three-dimensional persistent random walks. Physica A
Stadje, W. (1987). The exact probability distribution of a two-dimensional random walk. J. Statist. Phys.
Stadje, W. (1989). Exact probability distributions for non-correlated random walk models. J. Statist. Phys.
Vladimirov, V. S. (1981). The Equations of Mathematical Physics. Nauka, Moscow.