Ok, so this is not the WAM David Warren. But another David Warren who (for 25 years) has developed and refined XSB-Prolog.
David H. D. Warren (WAM): https://en.wikipedia.org/wiki/David_H._D._Warren
David S. Warren (XSB): https://scholar.google.co.uk/citations?user=6DDwarUAAAAJ&hl=...