B. Stephan, H. Zinner, F. Kastner, and A. Mannschreck, “Enantiomers of 2,2’-Spirobichromenes: Energy Barrier for Thermal Racemization during HPLC on Tribenzoylcellulose”, Chimia, vol. 44, no. 10, p. 336, Oct. 1990, doi: 10.2533/chimia.1990.336.