PT - JOURNAL ARTICLE AU - Brian R. Bruce TI - Editor’s Letter AID - 10.3905/jii.2019.9.4.001 DP - 2019 Mar 31 TA - The Journal of Index Investing PG - 1--2 VI - 9 IP - 4 4099 - https://pm-research.com/content/9/4/1.short 4100 - https://pm-research.com/content/9/4/1.full