Organic constituents on the surfaces of aerosol particles from southern Finland, Amazonia, and California studied by vibrational sum frequency generation - Ebben, Carlena J.; Shrestha, Mona; Martinez, Imee S.; Corrigan, Ashley L.; Frossard, Amanda A.; Song, Wei W.; Worton, David R.; Petäjä, Tuukka; Williams, Jonathan; Russel, Lynn M.; Kulmala, Markku; Goldstein, Allen H.; et al. (The Journal of Physical Chemistry A, 2012)