Perhaps you should try some spelling variations:
2.3.1.4 communication » 2.3.1.1 communication, 2.2.5.4 communication, 2.14 communication
population panel » population age, population based, population area
developpement la » developpement de, developpement et, developpement du
4 developpement » de developpement, le developpement, et developpement
technology tax » technology than, technology trap, technology tpm
tax population » farm population, fast population, boar population
firm 2.3.1.4 » fig 2.3.1.4, firm 2.3.5
la farce » la force, la face, la france
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 tax population panel firm 2.3.1.4 communication costs 4 developpement la farce.*.