TY - JOUR T1 - FTIR spectroscopic study on nickel(II)-exchanged sulfated alumina: nature of the active sites in the catalytic oligomerization of ethene A1 - Davydov, A. A A1 - Kantcheva, M. A1 - Chepotko, M.L. JA - Catalysis Letters Y1 - 2002 VL - 83 SP - 97 EP - 108 ER -