Expect to pay a good sum for them, either Ebay, or auto swaps are about your only bets.
There was also one brand that had it's own specific records (non-standard) that was aftermarket, but I forget which company, and that too was early sixties.
:Does anybody know if there has ever been a car record player for lps, that means 33 rpms? I know about the Philips car record player for 45 rpms. Does anybody know where I can get one of those? Please mail me!!