1. ITU‘Prediction of field strength at frequencies below about 150 kHz’, Recommendation ITU-R P. 684-3, 2002
2. ‘Low and very low frequency radio wave propagation’, July, 1968 p. 97–115 NATO AGARD Lecture Series 29, ‘Radio Wave Propagation’
3. ‘Ground-wave propagation curves for frequencies between 10 kHz and 30 MHz’, Recommendation, ITU-R P. 368-7, 1992