PT - JOURNAL ARTICLE AU - Allen Silver TI - Beta AID - 10.3905/jpm.1975.408534 DP - 1975 Jul 31 TA - The Journal of Portfolio Management PG - 54--60 VI - 1 IP - 4 4099 - https://pm-research.com/content/1/4/54.short 4100 - https://pm-research.com/content/1/4/54.full