Thayer, John S. (2010). "Relativistic Effects and the Chemistry of the Heavier Main Group Elements". In Barysz, Maria; Ishikawa, Yasuyuki (eds.). Relativistic Methods for Chemists. Springer. pp. 63–67. doi:10.1007/978-1-4020-9975-5_2. ISBN978-1-4020-9974-8.