N2H+ depletion in the massive protostellar cluster AFGL 5142 G. Busquet, R. Estalella, Q. Zhang, S. Viti, A. Palau, P. T. P. Ho and Á. Sánchez-Monge A&A, 525 (2011) A141 Published online: 09 December 2010 DOI: 10.1051/0004-6361/201014152