“A Polarimetric Search for Circumstellar Envelopes in the Young Clusters NGC 6611 and NGC 225”, RMxAA, vol. 1, no. 1, p. 283, Jan. 1974, Accessed: Dec. 11, 2025. [Online]. Available: https://astronomia.unam.mx/journals/rmxaa/article/view/1975rmxaa...1..283c