H. Sabbah, A. L. Morrow, A. E. Pomerantz, O. C. Mullins, X. Tan, M. R. Gray, K. Azyat, R. R. Tykwinski, and R. N. Zare, “Comparing Laser Desorption Laser Ionization Mass Spectra of Asphaltenes and Model Compounds,” Energy Fuels 24, 3589-3594 (2010).