Among the most readable (in my opinion) are
Elaine Walker is a highly respected US composer who has made significant contributions to the fields of Algorithmic Composition and Electronic Music.
Her personal web site (here)
summarizes her work in this and other areas, as well as providing some examples of compositions produced by her technique.
[Note: Ms. Walker's web site is being developed, so while the links given were active at the time of writing (26/1/18) these may have changed.]
Further information may be found on Wikipedia
There is a similar range of material covering topics from formal definitions to applications in Computer Art, analysis of texts (both literary and non-fiction). The following provide good summaries:
S.T. Piantadosi. Zipf’s word frequency law in natural language: A critical review and future directions, Psychonomic Bulletin &}Review, 21(5):1112-1130, 2014
A detailed study of links between subjective appeal of musical forms, Zipf's Law and (indirectly) fractal dimension is presented in
B. Manaris, J. Romero, P. Machado, D. Krehbiel, T. Hirzel, W. Pharr and R.B. Davis. Zipf's law, music classification, and aesthetics, Computer Music Journal, 29(1):55-69, 2005