Wampler, J.; et al. (May 1961), "Cepheids in Galactic Clusters. VIII. a Reinvestigation of U SGR in M25 (= IC 4725)", Astrophysical Journal, 133: 895, Bibcode:1961ApJ...133..895W, doi:10.1086/147092.
Majaess, D.; et al. (August 2024), "A Rare Cepheid-hosting Open Cluster Triad in Sagittarius", Research Notes of the AAS, 8 (8): 205, doi:10.3847/2515-5172/ad7139.
Wampler, J.; et al. (May 1961), "Cepheids in Galactic Clusters. VIII. a Reinvestigation of U SGR in M25 (= IC 4725)", Astrophysical Journal, 133: 895, Bibcode:1961ApJ...133..895W, doi:10.1086/147092.
Mermilliod, J. C.; et al. (September 1987), "Membership of cepheids and red giants in 8 open clusters : NGC 129, 6067, 6087, 6649, 6664, IC 4725, LY 6, RU 79", Astronomy and Astrophysics Supplement Series, 70: 389–407, Bibcode:1987A&AS...70..389M.
seds.org
messier.seds.org
"Messier 25". SEDS Messier Catalog. Retrieved 21 July 2024.