C. Mazet, V. Köhler, S. Roseblade, A. Toussaint, and A. Pfaltz, “Synthesis of Boron-Bridged Anionic C2-Symmetric Bisoxazolines and Their Application in Asymmetric Catalysis”, Chimia, vol. 60, no. 4, p. 195, Apr. 2006, doi: 10.2533/000942906777674958.