This definition appears somewhat frequently
See other definitions of OI
Samples in periodicals archive:
Painting/Coating Operations: Instructions for Emission Calculation Spreadsheet. This method may be used to develop an editable spreadsheet containing detailed...
Ditch witch parts list and operations instructions, model R40, 37HP trencher, Ditch Witch, model R65
OPNAVINST Chief of Naval Operations Instructions Navy Intelligence and Security Doctrine