Adam, W., Güthlein, M., Peters, E.-M., Peters, K., & Wirth, T. (1998). Chiral-auxiliary-induced diastereoselectivity in the [4 + 2] cycloadditions of optically active 2,2-dimethyloxazolidine derivatives of sorbic acid: a model study with singlet oxygen as the smallest dienophile. Journal of the American Chemical Society, 120, 4091-4093.