Campbell, S. R.; Ellingham, M. N.; Royle, Gordon F., A characterisation of well-covered cubic graphs, Journal of Combinatorial Mathematics and Combinatorial Computing, 1993, 13: 193–212, MR 1220613.
Henneberg, L., Die graphische Statik der starren Körper, Encyklopädie der Mathematischen Wissenschaften 4.1: 345–434, 1908. As cited by Coxeter (1950). See in particular p. 403.
books.google.com
Puzzle, Successful Farming, vol. 13, 1914: 50; A well and house puzzle, The Youth's Companion, vol. 90 no. 2, 1916: 392.
32. The fountain puzzle, The Magician's Own Book, Or, The Whole Art of Conjuring, New York: Dick & Fitzgerald: 276, 1857 [2018-08-27], (原始内容存档于2019-08-13).
32. The fountain puzzle, The Magician's Own Book, Or, The Whole Art of Conjuring, New York: Dick & Fitzgerald: 276, 1857 [2018-08-27], (原始内容存档于2019-08-13).