Kusner, Robert B.; Sullivan, John M. (1998), «On distortion and thickness of knots», Topology and geometry in polymer science (Minneapolis, MN, 1996), IMA Vol. Math. Appl., 103, New York: Springer, pp. 67–78, MR1655037, doi:10.1007/978-1-4612-1712-1_7
Kusner, Robert B.; Sullivan, John M. (1998), «On distortion and thickness of knots», Topology and geometry in polymer science (Minneapolis, MN, 1996), IMA Vol. Math. Appl., 103, New York: Springer, pp. 67–78, MR1655037, doi:10.1007/978-1-4612-1712-1_7