Vanmeerssche, M., Gilson, C., Germain, G., & Declercq, J.-P. (1981). Determination par diffraction de rayons × de la structure du diméthylamino-4 pentamethoxycarbonyl-1,2,3,5,5′ cyclopentadiene c17h21no10. Societes Chimiques Belges. Bulletin, 90(11), 1181-1182. https://doi.org/10.1002/bscb.19810901111 (Original work published 1981)