VestfridI. A. “Isometric Imbedding of Some Metric Spaces in l<sub class="a-Plus-plus">p</Sub&gt;-Spaces”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 53, no. 12, Dec. 2001, pp. 1718-23, https://umj.imath.kiev.ua/index.php/umj/article/view/4389.