Muegge, I., Ermler, U., Fritzsch, G., & Knapp, E. W. (1995). Free Energy of Cofactors at the Quinone-QA Site of the Photosynthetic Reaction Center of Rhodobacter sphaeroides Calculated by Minimizing the Statistical Error. The Journal of Physical Chemistry, 99(51), 17917-17925. doi:10.1021/j100051a017.