%0 Journal Article %A Robert F. Vandell %T Is Beta a Useful Measure of Security Risk? %D 1981 %R 10.3905/jpm.1981.23 %J The Journal of Portfolio Management %P 23-31 %V 7 %N 2 %U https://jpm.pm-research.com/content/iijpormgmt/7/2/23.full.pdf