Title:
Educational apparatus
United States Patent 2209157
Inventors:
Glunt, Omer M.
Publication Date:
07/23/1940
Export Citation:
Click for automatic bibliography generation
Assignee:
BELL TELEPHONE LABOR INC
Primary Class:
434/320
Other Classes:
2/339, 360/89, 369/53.1
International Classes:
G09B5/04; G11B5/00
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