Cite
Absorption and Space Reddening in the Galaxy as Shown by the Colors of Globular Clusters.
MLA
Stebbins, J. “Absorption and Space Reddening in the Galaxy as Shown by the Colors of Globular Clusters.” Proceedings of the National Academy of Sciences of the United States of America, vol. 19, no. 2, Feb. 1933, pp. 222–28. EBSCOhost, https://doi.org/10.1073/pnas.19.2.222.
APA
Stebbins, J. (1933). Absorption and Space Reddening in the Galaxy as Shown by the Colors of Globular Clusters. Proceedings of the National Academy of Sciences of the United States of America, 19(2), 222–228. https://doi.org/10.1073/pnas.19.2.222
Chicago
Stebbins, J. 1933. “Absorption and Space Reddening in the Galaxy as Shown by the Colors of Globular Clusters.” Proceedings of the National Academy of Sciences of the United States of America 19 (2): 222–28. doi:10.1073/pnas.19.2.222.