“A catalogue of galactic O stars and the ionization of the low density interstellar medium by runaway stars”., RMxAA, vol. 1, no. 1, pp. 211–259, Jan. 1974, Accessed: Dec. 10, 2025. [Online]. Available: https://astronomia.unam.mx/journals/rmxaa/article/view/1974rmxaa...1..211c