1. JBOT – An Easy QRP linear amplifier - https://www.vu2ese.com/index.php/2020/06/19/jbot-an-easy-qrp-linear-amplifier/
2. DK5JI: Countries with CEPT Licence (2023-03-12) - https://files.darc.de/index.php/s/CKT38kZP6miK7xf
3. The United States Frequency Allocation Chart - https://www.beautifulpublicdata.com/the-united-states-radio-frequency-allocation-chart/
4. Список українських постачальників компонентів - https://docs.google.com/spreadsheets/d/1vEC8ZElSIXJTsE8_0axEp6kBmYmTfmfnDcni1pl_hKw/edit#gid=0
5. Compact 20m Yagi - http://www.iw5edi.com/ham-radio/5872/compact-20m-yagi
** Six Meter Yagi Antenna - http://www.iw5edi.com/ham-radio/5886/six-meter-yagi-antenna