Reduced networks governing the fractional ionisation in interstellar molecular clouds J. G. L. Rae, N. Bell, T. W. Hartquist, M. J. Pilling and D. P. Ruffle A&A, 383 2 (2002) 738-746 Published online: 15 February 2002 DOI: 10.1051/0004-6361:20011748