Perhaps you should try some spelling variations:
"multi operations research : july 2009" » "poultry operations research : july 2009", "port operations research : july 2009", "court operations research : july 2009", "multi operations research : july 2006", "multi operations research : july 2013", "multi operations research : july 2012"
"bus operations research : july 2009" » "bus operators research : july 2009", "bank operations research : july 2009", "_ operations research : july 2009", "bus operations research : july 2006", "bus operations research : july 2013", "bus operations research : july 2012"

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