Where have you been looking, anyway? Old Cardboard is the best repository of info on this and many many sets, including the Pens.
http://www.oldcardboard.com/r/r313/r...?cardsetID=870
Start here, and if you really want the most info, order copies of issues 6 and 7. There is a lot of stuff there about all these sets that has never appeared anywhere else.
Cheers,
Tim