J. Crank, "The Mathematics of Diffusion"
1980 | ISBN: 0198534116, 0198533446 | 414 pages | PDF + DJVU | (7 + 4,2) MB
This classic diffusion text continues where many other texts end, and covers a broad variety of problem types. This is an excellent resource for diffusion solutions for less-common boundary conditions and assumptions, including thorough mathematical developments of the solutions and many references to the original works.