1. Hoard, S. L.; Hughes, R. E. InChemistry of Boron and its Compounds; Muetterties, E. L., Ed.; Wiley: New York, 1967; pp 25−154 and references therein to Hoard's and other's early work in the 1940s.
2. Analytical investigations in the BC system
3. Morosin, B.; Aselage, T. L.; Emin, D. InBoron-Rich Solids-1990; Emin, D., Aselage, T. L., Beckel, C., Switendick, A. C., Morosin, B., Eds.; American Institute of Physics: New York, 1991; p 193.