RT Journal Article SR Electronic T1 Changes in Corporate Credit Quality 1970–1990 JF The Journal of Fixed Income FD Institutional Investor Journals SP 7 OP 14 DO 10.3905/jfi.1992.408031 VO 1 IS 4 A1 Douglas J. Lucas A1 John G. Lonski YR 1992 UL https://pm-research.com/content/1/4/7.abstract AB