Petre, M., Fincher, S., Tenenberg, J., Anderson, R., Anderson, R., Bouvier, D., Fitzgerald, S., Gutschow, A., Haller, S., Jadud, M., Lewandowski, G., Lister, R., McCauley, R., McTaggart, J., Morrison, B., Murphy, L., Prasad, C., Richards, B., Sanders, K., Scott, T., Shinners-Kennedy, D., Thomas, L., Westbrook, S., & Zander, C. (2003). 'My criterion is: Is it a Boolean?': a card-sort elicitation of students' knowledge of programming constructs . Computing Laboratory Technical Report 6-03. University of Kent, Canterbury, UK.