RT Journal Article SR Electronic T1 Insurance seen and unseen JF The Journal of Portfolio Management FD Institutional Investor Journals SP 5 OP 8 DO 10.3905/jpm.1988.409164 VO 14 IS 4 A1 Sanford J. Grossman YR 1988 UL https://pm-research.com/content/14/4/5.abstract AB