United States patent digest, 1979, class 346
Subtitle: recorders.
Contributors: Boston Patent Company.
Publisher: Boston Patent Co.
Published: 1981
Place of publication: Needham Heights, Mass. (Post Office Box 55, Needham Heights 02194)
Language: eng
Number of pages: 133
Subjects: Recording instruments -- Patents.; Patents -- United States.
Other titles: Recorders.; U.S. patent digest, 1979, class 346.; US patent digest, 1979, class 346.
Notes: Spine title: U.S. patent digest, 1979, class 346.
Includes indexes.