Inventor

SAKAI MIZUHIRO

JP3 patents

Patents

3 patents

US7305558B1Dec 4, 2007

Digital signing method

HITACHI LTD38 citations91

US7770009B2Aug 3, 2010

Digital signing method

HITACHI LTD6 citations72

US7707079B2Apr 27, 2010

Tax declaration system

HITACHI LTD0 citations31