Vazquez, R. A.; Feinstein, A. (1992). "Binary stars - Another effect contributing to the supposed abnormal extinction law in NGC 6193?". Astronomy and Astrophysics Supplement Series. 92: 863. Bibcode:1992A&AS...92..863V.
Herbst, W.; Havlen, R. J. (1977). "ARA OB1, NGC 6193 and ARA R1 - an optical study of a very young southern complex". Astronomy and Astrophysics Supplement Series. 30: 279. Bibcode:1977A&AS...30..279H.
Moffat, A. F. J.; Vogt, N. (1973). "Southern open stars clusters. III. UBV-Hbeta photometry of 28 clusters between galactic longitudes 297d and 353d". Astronomy and Astrophysics Supplement Series. 10: 135. Bibcode:1973A&AS...10..135M.