N. Wakao et al., "Discovery of Natural Photosynthesis using Zn-Containing Bacteriochlorophyll in an Aerobic Bacterium Acidiphilium rubrum", Plant and Cell Physiology37, 889-893 (1996)., doi:10.1093/oxfordjournals.pcp.a029029
Chen M, Schliep M, Willows RD, Cai ZL, Neilan BA, Scheer H., "A red-shifted chlorophyll." Science. 2010 Sep 10;329(5997):1318-9. doi:10.1126/science.1191127