Perhaps you should try some spelling variations:
2.3.1.2 communication » 2.3.1.1 communication, 2.2.5.4 communication, 3.2.3.2 communication
population panel » population age, population based, population area
developpement en » developpement et, developpement des, developpement de
technology trap » technology trade, technology tax, technology than
trap population » rural population, rapid population, boar population
a developpement » au developpement, de developpement, le developpement
fig 2.3.1.2 » fig 2.3.1.3, fig 2.3.1.4, fig 2.3.1.5
panel fig » panel firm, panel i, panel ii
costs a » costs _, costs 4

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

• Adding a wildcard symbol may retrieve word variants: technology trap population panel fig 2.3.1.2 communication costs a developpement en france.*.