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公开(公告)号:US2572460A
公开(公告)日:1951-10-23
申请号:US7565549
申请日:1949-02-10
Applicant: ALBRECHT FALK GERHARD ERNST
Inventor: ALBRECHT FALK GERHARD ERNST
IPC: G09B29/04
CPC classification number: G09B29/04
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2.
公开(公告)号:US2615732A
公开(公告)日:1952-10-28
申请号:US14963150
申请日:1950-03-14
Applicant: ALBRECHT FALK GERHARD ERNST
Inventor: ALBRECHT FALK GERHARD ERNST
IPC: G09B29/04
CPC classification number: G09B29/04
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