Perhaps you should try some spelling variations:
3.3 communication » 2.3 communication, 3.2 communication, 3.5 communication
study population » student population, student populations, city population
population case » population based, population age, population change
4 developpement » de developpement, le developpement, et developpement
developpement l » developpement il, developpement la, developpement de
case frame » based frame, scale frame, case from
frame 3.3 » frame 1.3, frame 3.4, frame 3.3.2
l afrique » en afrique
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: technology study population case frame 3.3 communication costs 4 developpement l afrique.*.