Perhaps you should try some spelling variations:
opec communication » open communication, optic communication, ec communication
developpement la » developpement de, developpement et, developpement du
variation des » variation _, variation 6, variation series
la afrique » l afrique, la fabrique, en afrique
dem opec » der opec, des opec, die opec
des dem » das dem, des der, des des
a der » _ der, 2 der, 3 der
a de » a die, a des, _ de

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "typology _ variation des dem opec communication ((a de) OR (a der)) developpement la afrique.~".
• Adding a wildcard symbol may retrieve word variants: typology _ variation des dem opec communication ((a de) OR (a der)) developpement la afrique.*.