RT Journal Article SR Electronic T1 Bid-ask spreads, NYSE specialists, and NASD dealers JF The Journal of Portfolio Management FD Institutional Investor Journals SP 54 OP 58 DO 10.3905/jpm.1991.409381 VO 18 IS 1 A1 Steven V. Mann A1 Robert W. Seijas YR 1991 UL https://pm-research.com/content/18/1/54.abstract AB