Perhaps you should try some spelling variations:
persona communication » personal communication, personal communications, personal communicator
du developpement » de developpement, le developpement, et developpement
developpement de » developpement des, developpement durable
gamma variables » dummy variables, data variables, same variables
typology gamma » typology alma
variables 4 » variables _, variables 2.3
die persona » die person, de persona, die personale
4 die » 2 die, 3 die, _ die
a du » a d, a de, a u

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

• Adding a wildcard symbol may retrieve word variants: typology gamma variables 4 die persona communication a du developpement de l'afrique.*.