Kita, K., Y. Morino, Y. Kondo, Y. Komazaki, . Takegawa, Y. Miyazaki, J. Hirokawa, S. Tanaka, T. Thompson, R. Gao, and D.W. Fahey (2006), A chemical ionization mass spectrometer for ground-based measurements of nitric acid, J. Atmos. Oceanic Technol., 23, 1104-1113.