This is the best resource I’ve found, joy to read, self contained, explains mysterious Codon mapping mentioned in Anastassiou’s 2001 IEEE Spectrum article
Digital signal processing approaches for estimation of codon bias and replication origin sites in prokaryotic genomes. By Ahsan Z Rizvi
by Dimitris Anastasiou
https://faculty.coe.drexel.edu/gailr/class_papers/anastassiou.pdf
Paul Dan Cristea, 2004
https://prod-files-secure.s3.us-west-2.amazonaws.com/a58a63b0-91bf-47b9-8b7f-c24b0066faa3/abab0c48-3a65-4724-87ea-5fb90eec2364/2002-LargeScaleFeatuesInDnaGenomicSignals.pdf
by. V.V. Vaidyanathan, 2004
https://apps.dtic.mil/sti/tr/pdf/ADA427792.pdf
Dougherty, Shmulevich, Chen and Wang, 2005