Bob's nickname was “Elvis,” a 'reference to' the way he styled his hair. [=people called Bob “Elvis” because he styled his hair in the same way Elvis Presley did]
The course covers ancient history 'with' special 'reference to' the Roman Empire. [=the course is about ancient history and especially about the Roman Empire]
I have something further to add 'with reference to' [='with respect to', 'in regard to'] what was said earlier.
(..) and the energy-storage capacity of Kryptonian skin cells. I'm just gonna go wash up. I have comic books in there. I challenge you to find a single reference to Kryptonian skin cells. Challenge accepted. We're locked out. Also, the pretty girl left. o/~ Our whole universe (..)2007 TvShow: The Big Bang Theory Title: The Big Bran Hypothesis Season: 1 Episode 2