Perhaps you should try some spelling variations:
4.1 communication » 4 communication, 2.3 communication, 3.2 communication
4.2 developpement » 4.2 development, de developpement, le developpement
developpement de » developpement des, developpement durable
risk population » risk populations, drive population, risk regulation
population wage » population age, population wide, population aged
de afrique » de l'afrique, en afrique, l afrique
wage rate » wage rates
rate 4.1 » rates 4.1, rate 4.3, rate 4.2

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

• Adding a wildcard symbol may retrieve word variants: technology risk population wage rate 4.1 communication costs 4.2 developpement de afrique.*.