1. US 8.779.125 (2013); US 8.124.184 (2010); US 7.842.640 (2010 Exxon); US 5.716.897 (1998 UOP); US 5.912.393 (1999 UOP); van Bekkum/Flanigen/Jacobs/Jansen p.51;
2. Clerici/Kholdeeva; Thomas/Thomas; Ertl/Knözinger/Weitkamp p. 343 377;
3. A new catalyst for the synthesis of N,N-biphenylurea from aniline and dimethyl carbonate