: 'Discussion on “Crystal resonators as frequency substandards”', Proceedings of the IEE - Part III: Radio and Communication Engineering, 1950, 97, (48), p. 252-252, DOI: 10.1049/pi-3.1950.0046
IET Digital Library, https://digital-library.theiet.org/;jsessionid=2n6xx09ae53fo.x-iet-live-01content/journals/10.1049/pi-3.1950.0046