Das Grosse Buch der D&D Regeln

Thanks to Paul Stormberg for the scan.

D&D Rules Encyclopedia

Thanks to Yony for the scan.

D&D Rules Cyclopedia (3 volumes)

Three digest-sized volumes, entitled D&D Rules Encyclopedia: Players, D&D Rules Encyclopedia: Dungeon Masters, and D&D Rules Encyclopedia: Monsters.  Thanks to Adrian Newman for this info, and the scans.