The standard reference on So-Called Dollars was written by Harold E. Hibler and Charles V. Kappen. An initiallisting was compiled by Richard D. Kenney and published by Wayte Raymond in 1953. Hibler began to compile anupdate and Kappen joined the project later. The book was published by Robert Friedberg's Coin and CurrencyInstitute. American Numismatic Biographies has a fairly extensive write-up for Kappen.

The write-up for Harold Hibler is notably meager.

Harold Hibler was the son of Christopher Arthur Hibler (1873-1924) and Louise Isabelle Eisenbise Hibler (1874-1932).

Kappen joined the ANA as member 12047 in 1946. Hibler was not listed as an ANA member. He was a member and Trustee of the Boston Numismatic Society. He was a manager for Aetna Insurance in Boston and promoted to vice president in New York in 1963.

Hibler died in Broward County, Florida, and is buried with Doris at Mount Auburn Cemetery in Cambridge, Massachusetts.

To read the earlier E-Sylum article, see:
LOUIS ELIASBERG, SR. AND JR.(https://www.coinbooks.org/v24/esylum_v24n33a16.html)