i was able to find a bunch of Anne McCaffrey's works either at Amazon or at webscription.net, but not those three. I'll have to do some searching to see if it's available at some other website.
another author i was really surprized to see so little available was Robert A. Heinlein. I mean what the heck? He's one of the biggies in the history of scifi and the books are old, so you'd think publishers would be falling over themselves trying to get additional revenue streams out of properties that they already own that have been out there. Hmm... geeks read scifi... would geeks be early adopters of electronic gadgets like ereaders?... hmm...

Luckily, amazon had a couple Heinlein books and webscription had an entirely different set of Heinlein books. Still not a lot and of course my faves were missing. sigh.
I'm definitely going to have to go through my dead-tree book collection and start putting together a pile to give away to the library, decide what I'll keep as dead-tree format, and what I need to get in digital format. Then of course, the need-to-get-in-digital list will have to be prioritized unless I win the lottery.

Hehe, my book list is already three pages long and several of the entries are big collections. I'm already over the half-way point on the Kindle storage! Must find my extra SD card...