Perhaps you should try some spelling variations:
oral communication » personal communication
du developpement » de developpement, le developpement, et developpement
der variation » de variation, does variation, die variation
typology der » typologie der, typologien der, typologie des
des afrique » en afrique, de l'afrique
6 first » 2 first, 1 first, 4 first
3 first » 2 first, 3.1 first

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 der variation ((6 first) OR (3 first)) oral communication _ du developpement des afrique.~".
• Adding a wildcard symbol may retrieve word variants: typology der variation ((6 first) OR (3 first)) oral communication _ du developpement des afrique.*.