1.
[Place of publication not identified] : [publisher not identified], 1967.
German | R 71 WEN.R |
2.
Cologne [Germany] : German Association for the Protection of Intellectual Property (GRUR), 1972.
German | 28 DE |
3.
Cologne [Germany] : German Association for the Protection of Intellectual Property (GRUR), 1991.
German | 28 DE |