M. Müller, P. Eichler, W. Tan, B. D'Anna, A. Wisthaler: "Direct Sampling and Analysis of Atmospheric Particulate Organic Matter by Proton-Transfer-Reaction Mass Spectrometry", Analytical Chemistry, available online 15 September 2017. http://pubs.acs.org/doi/abs/10.1021/acs.analchem.7b02582