http://www.dwightdiller.com/bluegrass.html
It does mention IrTrad briefly, and is perhaps relevant to it in some ways. (In particular, to how it relates to less traditional modern variants.)
The note on the author says:
Allen Feldman has been playing oldtime and Irish music on clawhammer banjo and cittern since the 1960s. He is the author of the Northern Fiddler: Music and Musicians of Donegal and Tyrone, Blackstaff Press, 1980.
I went to an Old-Time banjo/fiddle concert (Dan Levinson, the Lovely Miss Jennifer, and Bob Carlin) last night, and will be going to Dan’s clawhammer banjo workshop tomorrow. Since I haven’t attempted clawhammer in about 30 years, I’ve been out around the Web looking at sites to get just a little start on the workshop, which is how I ran across this.