Cross-sections for rotational excitations of C3H4 isomers by electron impact A. R. Lopes, M. H.F. Bettega, M.T. do N. Varella and M. A.P. Lima Eur. Phys. J. D, 37 3 (2006) 385-392 Published online: 13 December 2005 DOI: 10.1140/epjd/e2005-00330-3