Interesting. I wonder whose that is, and how long ago it was put together.
These studies vary a lot in completeness and quality. Its not like one chart is the same as others. Its also always hard to tell what's really in them from auction descriptions, because they don't illustrate the whole thing ever for these.
In my case, I sent Bill my entire 3c collection, and he kept it for a couple weeks and sent me back a very nice chart that he made from it. I added some things to it over time, that he double checked for me.
For what its worth, mine was here, although they don't illustrate much. Same issue with the one in the current sale. Also, on mine to further confuse things, they photo-shopped individual stamps together and made it look like that was a single card. It wasn't - those were on all different cards with lots of other stamps.
http://www.bennettstamps.com/cgi-bi...=1332&lang=1edit: While I'm reminiscing, this was a stunning Reddish OB, that I found at a local stamp show. Of course not identified.
http://www.bennettstamps.com/cgi-bi...=1341&lang=1