Patent:US2910786

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Brevetto:US 2910786
Titolo:Calculating device for teaching arithmetic
Data:03.11.1959
Luogo:
Nazione:Stati Uniti
Persona:Howard Healey, Cohn Irwin
Ditta:Great American Plastics Co
Link interni:
Keywords:
Link al brevetto:
(without guarantee)
 US2910786 (http://v3.espacenet.com/textdoc?DB=EPODOC&F=0&IDX=US2910786) (espacenet),  US2910786 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/FPTO/srchnum.htm&r=1&f=G&l=50&s1=2910786.PN.&OS=PN/2910786&RS=PN/2910786) (uspto)


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Ultima modifica il 12:09, 15. Mar 2009.