Effects of task difficulty and type of contingency on students' allocation of responding to math worksheets.

per Lannie, Amanda L, Martens, Brian K
Publicat 2004

Sensitivity of children's behavior to probabilistic reward: effects of a decreasing-ratio lottery system on math performance.

per Martens, Brian K, Ardoin, Scott P, Hilt, Alexandra M, Lannie, Amanda L, Panahon, Carlos J, Wolfe, Laurie A
Publicat 2002