PT - JOURNAL ARTICLE AU - Michael G. Ferri AU - Charles G. Martin TI - The cyclical pattern in corporate bond quality AID - 10.3905/jpm.1980.408736 DP - 1980 Jan 31 TA - The Journal of Portfolio Management PG - 26--29 VI - 6 IP - 2 4099 - https://pm-research.com/content/6/2/26.short 4100 - https://pm-research.com/content/6/2/26.full