“Spectrophotometry of Northern Wolf-Rayet Stars: A Sample of WN4, WN5 and WN6 Stars”. Revista Mexicana De Astronomía Y Astrofísica, vol. 14, no. 1, Jan. 1987, pp. 284-6, https://astronomia.unam.mx/journals/rmxaa/article/view/1987rmxaa. 14. 284b.