Williamson started his international career in 2010 refereeing Japan v Samoa in Tokyo.
David Williamson | Robin Williamson | Williamson County | Jack Williamson | Alison Williamson | Williamson County, Tennessee | Sonny Boy Williamson II | John Williamson | Brown & Williamson | Fred Williamson | Williamson | Skip Williamson | John Williamson (singer) | Williamson County, Texas | Nicol Williamson | Marianne Williamson | J. C. Williamson | Allen Williamson (Representative) | Allen Williamson Bridge | Allen Williamson | South Williamson, Kentucky | South Williamson | Sonny Boy Williamson | Shaun Williamson | Robert Williamson III | Norris C. Williamson | Kay Williamson | James Williamson (film pioneer) | James Williamson | Harry Williamson |