The analysis of error in trace gas concentration measurements by intermodulated photoacoustic stark spectroscopy (IMPASS) T. Groot, D. Bicanic, M. van Montfort, P. Torfs, R. Braun and K. van Asselt J. Phys. IV France, 04 C7 (1994) C7-519-C7-522 DOI: 10.1051/jp4:19947122