Hill, M.N.; Laughton, A.S. (1954). "Seismic Observations in the Eastern Atlantic, 1952". Proceedings of the Royal Society of London A: Mathematical and Physical Sciences. 222 (1150): 348–356. Bibcode:1954RSPSA.222..348H. doi:10.1098/rspa.1954.0078. S2CID140604584.
Hill, M.N.; Laughton, A.S. (1954). "Seismic Observations in the Eastern Atlantic, 1952". Proceedings of the Royal Society of London A: Mathematical and Physical Sciences. 222 (1150): 348–356. Bibcode:1954RSPSA.222..348H. doi:10.1098/rspa.1954.0078. S2CID140604584.
Hill, M.N.; Laughton, A.S. (1954). "Seismic Observations in the Eastern Atlantic, 1952". Proceedings of the Royal Society of London A: Mathematical and Physical Sciences. 222 (1150): 348–356. Bibcode:1954RSPSA.222..348H. doi:10.1098/rspa.1954.0078. S2CID140604584.