Half bewust morse leren:

https://www.scientificamerican.com/article/how-to-learn-morse-code-mdash-semiconsciously/

Vrijgegeven CIA-documenten over zendamateurs in de voormalige Sovjet-Unie:

https://www.cia.gov/library/readingroom/search/site/amateur%20ham%20radio

De Walkie Talkie Duino:

https://www.tindie.com/products/masihvahida/walkie-talkie-duino/?utm_source=amateur-radio-weekly&utm_medium=email&utm_campaign=newsletter