Maier,L.
Angewandte Chemie, 1969 , vol. 81, p. 154

I.G.Farbenind.
Patent: DE724759 , 1937 ;
DRP/DRBP Org.Chem.

Roche Vitamins Inc.
Patent: US6359132 B1, 2002 ;
Location in patent: Example 2 ;

Kazantsev, O. A.; Shirshin, K. V.; Kazakov, S. A.; Danov, S. M.
Russian Journal of Applied Chemistry, 1999 , vol. 72, # 1 p. 152 - 155
Zhurnal Prikladnoi Khimii (Sankt-Peterburg, Russian Federation), 1999 , vol. 72, # 1 p. 143 - 147