RT Journal Article SR Electronic T1 Rating Drift in High-Yield Bonds JF The Journal of Fixed Income FD Institutional Investor Journals SP 15 OP 20 DO 10.3905/jfi.1992.408035 VO 1 IS 4 A1 Edward I. Altman A1 Duen Li Kao YR 1992 UL https://pm-research.com/content/1/4/15.abstract AB