Please refer following research articles for more details:

• Kolekar P., Kale M., Kulkarni-Kale U., Alignment-free distance measure based on return time distribution for sequence analysis: Applications to clustering, molecular phylogeny and subtyping, Molecular Phylogenetics and Evolution, (2012) 65(2): 510-522. [PMID: 22820020] Download: Authors' preprint and Supplementary file
  
  
• Kolekar, P., Hake, N., Kale, M., Kulkarni-Kale, U., WNV Typer: A server for genotyping of West Nile viruses using an alignment-free method based on a return time distribution, Journal of Virological Methods, (2013) 198: 41-55. [PMID: 24388930]
  
  
• Kolekar, Pandurang, Kale, Mohan, and Kulkarni-Kale, Urmila. Subtyping of Dengue Viruses using Return Time Distribution based Appproach. Available from Nature Precedings (2011)
  
  
• Kolekar P, Kale M, Kulkarni Kale U: Genotyping of Mumps viruses based on SH gene: Development of a server using alignment-free and alignment-based methods. Immunome Research, 2011, 7(3):1-7 [Publisher's full text]