Find peer-reviewed, published research using the Inquisit Number Letter Task
Rogers, R. D., & Monsell, S. (1995). The costs of a predictable switch
between simple cognitive tasks. Journal of Experimental Psychology:
General, 124, 207–231.
Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, A.,
& Wager, T. D. (2000). The unity and diversity of executive functions
and their contributions to complex “frontal lobe” tasks: A latent variable
analysis. Cognitive Psychology, 41, 49–100.