2Zhao Motian, Wang Jun, Lu Baikeng, et al. Application of Isotope Dilution Mass Spectrometry to Research of Certified Reference Materials[J]. Accred Qual Assur, 2002, 7:111-114.
3Gunther, Barkley, Kolbezen, Blinn, Staggs. " Quantitative Microdetermination of Gaseuos Ammonia by Its Absorption" University of California, 1956,28(12) : 12