Autor:	McDowell, C. M., Usher, F. L.
Zdroj:	Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1932 Oct 01. 138(834), 133-146.
Databáze:	JSTOR Journals
Externí odkaz:	https://www.jstor.org/stable/96013 Zobrazit plný text záznamu