References:
"Resnick, M., Maloney, J., Monroy-Hernandez, A., Rusk, N., Eastmond, E., Brennan, K., Millner, A., Rosenbaum, E., Silver, J., Silverman, B., & Kafai, Y. (2009). Scratch: Programming for All. Communications of the ACM, vol. 52, no. 11, pp. 60-67 (Nov. 2009).
http://www.media.mit.edu/~mres/papers/Scratch-CACM-final.pdf
Maloney, J., Resnick, M., Rusk, N., Silverman, B., & Eastmond, E. (2010). The Scratch Programming Language and Environment. ACM Transactions on Computing Education (TOCE), vol. 10, no. 4 (November 2010).
http://web.media.mit.edu/~jmaloney/papers/ScratchLangAndEnvironment.pdf
"