"U.S. Frequency Allocation Chart"(PDF). National Telecommunications and Information Administration, U.S. Department of Commerce. October 2003. Diarsipkan(PDF) dari versi asli tanggal 2008-03-09. Diakses tanggal 2009-08-11.
"Ground wave MF and HF propagation"(PDF). Introduction to HF Propagation. IPS Radio and Space Services, Sydney Australia. Diarsipkan dari versi asli(PDF) tanggal 2015-08-02. Diakses tanggal 27 September 2010.
"Ground wave MF and HF propagation"(PDF). Introduction to HF Propagation. IPS Radio and Space Services, Sydney Australia. Diarsipkan dari versi asli(PDF) tanggal 2015-08-02. Diakses tanggal 27 September 2010.
"U.S. Frequency Allocation Chart"(PDF). National Telecommunications and Information Administration, U.S. Department of Commerce. October 2003. Diarsipkan(PDF) dari versi asli tanggal 2008-03-09. Diakses tanggal 2009-08-11.