As originals, all the ones mentioned are long out-of-print so you will have to find them used. At least two have been reissued and may still be available as reissues through the usual mail order sources. Speakers Corner reissued the Jochum/DGG recording (DGG SLPM 139362) and it still shows as in-print on their website (but they do not sell direct). I believe Testament once reissued the DeBurgos, but I don't know of any source for that new today. I've heard that the Kegel was once reissued, perhaps by Speakers Corner, but I've never found a source.
In the used market, the Jochum/DGG appears regularly for $10 or so.
In the used market, the Jochum/DGG appears regularly for $10 or so.