[78-L] JATP Albums on Disc and Mercury Label Records

[78records at cdbpdx.com]

I just brought home JATP Vol 4 album on the DISC label.  Inside was a 16 page 'program' talking about JATP albums on Mercury label, Vol 6 - Vol 8.  Is this program original to the DISC album?  You can view scans of the program here:
 
http://78records.cdbpdx.com/JATP/
 
Did DISC make the early JATP albums, then MERCURY made the rest?  Or did Mercury release the originally then DISC re-issue them?  I guess I am confused about the chronology of releases and which labels were used.  Any comments?
 
Thanks!  Cliff