Perhaps you should try some spelling variations:
oral communication » personal communication
der developpement » de developpement, des developpements, leur developpement
developpement en » developpement et, developpement des, developpement de
der variation » de variation, does variation, die variation
variation key » variation des, variation bei, variation der
key items » key item, prey items, key ideas
theorie » theories

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

• Adding a wildcard symbol may retrieve word variants: theorie der variation key items oral communication _ der developpement en afrique.*.