Ravensburger (and other publishers) used to licence their games, especially compilations, to a big distributor, that has its own distribution channels. Mostly, their products are available for members only.
The content of the games is often identical, sometimes with variations (cheaper components, skipped rules), the price is lower than the regular one, especially for compilations.
Bertelsmann is the book club mentioned first, but the licence is (always?) for all these publishers:
Europäische Bildungsgemeinschaft Verlags-GmbH
Buchgemeinschaft Donauland Kremayr & Scherlau
Deutsche Buch-Gemeinschaft C.A. Koch's Nachf.
Source: Rules of the compilation Grand Prix & Jockey
In the seventies, they used the logo SPIELE CLUB EXCLUSIV
The product numbers (always?) begin with 9