1. O. D. Kellogg,Foundations of Potential Theory, Springer, Berlin, 1929.
2. George Green,Mathematical Papers, ed. N. Ferrers, Macmillan, London, 1871; reprint, Chelsea, New York, 1970.
3. For information on Murphy, see W. Thomson,Reprint of Papers on Electrostatics and Magnetism, Macmillan, London, 1872, 1–2 and 126.
4. S. P. Thompson,Life of Lord Kelvin.Chelsea, New York, 1976, vol. 1, 113–119.