1
Bo Lofberg: Method and apparatus for marking the information content of an information carrying signal. Frishauf Holtz Goodman & Woodward, July 9, 1985: US04528588 (434 worldwide citation)

An information signal (INF) which is transmitted in coded form (CINF) from a signal source (RC) to a signal receiver (4,5) is decoded at the receiver and at the same time marked (MINF) by the introduction of an identification information (ID) which is characteristic of the receiver or its possessor. ...


2
Bo Lofberg: Data carrier. Frishauf Holtz Goodman & Woodward, April 15, 1986: US04582985 (417 worldwide citation)

A data carrier (preferably shaped as a credit card or the like) holds information about the owner, card issuing organization, account number, etc., and comprises an internal processor for processing supplied identification information of the owner during a card verification process, and for generati ...


3
Bo Lofberg: Method and apparatus for marking the information content of an information carrying signal. Frishauf Holtz Goodman & Woodward, June 17, 1986: US04595950 (329 worldwide citation)

An information signal (INF) which is transmitted in coded form (CINF) from a signal source (RC) to a signal receiver (4, 5) is decoded at the receiver and at the same time marked (MINF) by the introduction of an identification information (ID) which is characteristic of the receiver or its possessor ...