Cleeton, C. E.; Williams, N. H. (1934). "Electromagnetic Waves of 1.1 cm Wave-Length and the Absorption Spectrum of Ammonia". Phys. Rev. 45: 234. Bibcode:1934PhRv...45..234C. doi:10.1103/PhysRev.45.234.
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Cleeton, C. E.; Williams, N. H. (1934). "Electromagnetic Waves of 1.1 cm Wave-Length and the Absorption Spectrum of Ammonia". Phys. Rev. 45: 234. Bibcode:1934PhRv...45..234C. doi:10.1103/PhysRev.45.234.