Here are their sources:
1. Blomstrand, E., Eliasson, J., Karlsson, H.K., and Kohnke, R. (2006). Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr 136, 269S-273S.
2. Shimomura, Y., Yamamoto, Y., Bajotto, G., Sato, J., Murakami, T., Shimomura...