Clemens J.C., R.E. Nather, D.E. Winget, E.L. Robinson, M.A. Wood, C.F. Claver, J.L. Provencal, S.J. Kleinman, P.A. Bradley, M.L. Frueh, and A.D. Grauer, The Astrophysical Journal 391, 773 (1992).
Winget D.E., R.E. Nather, J.C. Clemens, J.L. Provencal, S.J. Kleinman, P.A. Bradley, M.A. Wood, C.F. Claver, E.L. Robinson, A.D. Grauer, and B.P. Hine, The Astrophysical Journal 357, 630 (1990).