Galloway, E., Armbrüster, M., Kovnir, K., Tikhov, M. S., & Lambert, R. M. (2009). Bromine-promoted PtZn is very effective for the chemoselective hydrogenation of crotonaldehyde. Journal of Catalysis, 261, 60-65. doi:10.1016/j.jcat.2008.11.003.