1. "1. N. I. Ionescu and C. Hornoiu, in "Form and Patterns", C. Vasilescu, M.-L. Flonta and I. Craciun (Eds.), Roumanian Academy Printing House, 2015, p.166.
2. 2. G. Ertl, Adv. Catal., 1990, 37, 213.
3. 3. F. Schuth, B. E. Henry and L.D. Schmidt, Adv. Catal., 1993, 39, 51.
4. 4. M.M. Slinko and N. I. Jaeger, Studies in Surf. Sci. Catal., 1994, 86, 408.
5. 5. R. Imbihl, Topics Catal., 2005, 105, 206.