The 1955 paper by James Power Gordon, Herbert Jack Zeiger and Charles Hard Townes acknowledged Nikolay Basov and Aleksandr Prokhorov's independent proposal.[ref]
The Maser—New Type of Microwave Amplifier, Frequency Standard, and Spectrometer by James Power Gordon and others. p. 1264, Introduction and reference 2
The latter authors' theory paper states that they presented the molecular-generator possibility in May 1952, cites their 1954 publication, and separately cites the Gordon–Zeiger–Townes experimental realization. These are contributions from independent groups.[ref]Theory of the Molecular Generator and Molecular Power Amplifier by Nicolay Gennadiyevich Basov and Aleksandr Mikhailovich Prokhorov. p. 426, historical footnote and references 3–4; manuscript submitted December 10, 1954, English publication October 1956
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