Perhaps you should try some spelling variations:
"call options research : july 2011" » "call operations research : july 2011", "call action research : july 2011", "call opinion research : july 2011", "call option research : july 2011", "real options research : july 2011", "call options research : july 2013", "call options research : june 2011"
"scale options research : july 2012" » "scale operations research : july 2012", "scale action research : july 2012", "scale opinion research : july 2012", "share options research : july 2012", "care options research : july 2012", "case options research : july 2012", "scale options research : july 2013"

You may be able to get more results by adjusting your search query.

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