1. Nitric oxide reduction by methane over Rh/Al2O3 catalysts
2. M. Schneider, K. Kochloefl and D. Prigge, DE Pat., OS 3428231 A1
3. E.M. Nekhrich, Yu.P. Khlebnikov and E.V. Reshetnyak, SU Pat. 1097370
4. H. Inaba, S. Onizuka and Y. Kamino, DE Pat. OS 2433479