Dirkx, K. J. H. (2014, 11 April). Putting the testing effect to the test. Why and when is testing effective for learning in secondary school. Unpublished doctoral dissertation. Heerlen: Open University of the NetherlandsIn this doctoral thesis the testing effect is investigated among secondary school students. It includes 5 different studies.NWO the Netherlands organization for scientific research. Project no. 451.07.00