Texts on Diamond Jubilee Series

Hello all,
I am very new to learning Gregg shorthand and am thrilled to have learned the basic outlines. I currently own GREGG SHORTHAND, GREGG DICTATION, GREGG SHORTHAND DICTIONARY, and both volumes of GREGG SHORTHAND FOR COLLEGES all in the Diamond Jubilee Series. Are there other workbooks or textbooks that would be good to find and purchase? If so, where is the best place online to look for Gregg books on shorthand? I am wanting to complete set for the DJ Series and I don't know what I'm missing. Please advise. Thank you very much, Mark

(by shorthandmark for everyone)