GEZA VERMES: Was Crucifixion a Jewish Penalty? (Standpoint Magazine).
The doctoral dissertation by Gunnar Samuelsson discussed in the article is noted here and links.
Tangentially related (via crucifixion—'tis the season) from Bible History Daily: The Staurogram: The earliest images of Jesus on the cross. I noted a lecture by Larry Hurtado on the subject (as well as his book) in 2007, here.
