Golasinski, M., D. Goncalves, and P. Wong. “Generalizations of Fox Homotopy Groups, Whitehead Products, and Gottlieb Groups”. Ukrains’kyi Matematychnyi Zhurnal 57, no. 3 (March 25, 2005): 320–328. Accessed May 19, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3600.