RT Journal Article SR Electronic T1 Variances and Option Prices in Theory and Practise JF The Journal of Portfolio Management FD Institutional Investor Journals SP 43 OP 51 DO 10.3905/jpm.1978.408631 VO 4 IS 2 A1 Richard J. Rogalski YR 1978 UL https://pm-research.com/content/4/2/43.abstract AB