Perhaps you should try some spelling variations:
"multi operations research : july 2009" » "poultry operations research : july 2009", "bus operations research : july 2009", "court operations research : july 2009", "multi operations research : july 2006", "multi operations research : july 2013", "multi operations research : july 2012"
"port operations research : july 2009" » "market operations research : july 2009", "group operations research : july 2009", "transport operations research : july 2009", "port operations research : july 2006", "port operations research : july 2013", "port operations research : july 2012"

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