Ward Silver, Mark Wilson, "The ARRL Extra Class License Manual: For Ham Radio, 9th Edition" English | 2008 | ISBN: 0872591352 | 500 pages | PDF | 80.77 MB
Stephen Horan, "Amateur Radio Technician Class Licensing: For 2022 through 2026 License Examinations" English | 2022 | ASIN: B09WQ4ZDRK, B09X3JKJVK | EPUB | pages: 211 | 4.2 mb