Perhaps you should try some spelling variations:
personal communication » interpersonal communication
developing state » developing states, developing stable, developing strategy
models personal » model personal, des personal, roles personal
technologies 2 » technologies _, technologies 4
information 1 » information 2, information 3, information 3.2
4 developing » 3 developing
state africa » trade africa
1 models » 17 models, 2 models, 3 models
costs 4 » costs _, costs a, costs 4.2

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

• Adding a wildcard symbol may retrieve word variants: technologies 2 information 1 models personal communication costs 4 developing state africa.*.