1. H. Steinberg, Organoboron Chemistry, vol. 1: Boron-Oxygen and Boron-Sulfur Compounds (Wiley, New York, 1963).
2. E. M. Schwartz, Interaction of Boric Acid with Alcohols and Hydroxy Acids (Zinatne, Riga, 1990) [in Russian].
3. F. H. Allen, Acta Crystallogr., Sect. B: Struct. Sci. 58, 380 (2002).
4. E. Bessler and J. Weidlein, Z. Naturforsch., B: Chem. Sci. 37(8), 1020 (1982).
5. I. I. Zviedre and E. M. Schwartz, Latv. Khim. Zh., No. 1, 83 (2005).