International Philatelic Association

Came across this booklet and was wondering if anyone knew the history of the International Philatelic Association and/or the persons listed (i.e. front H.F. Christensen, Exchange Manager, Emerson, NJ and reverse L.J. Flerlage, Norwood, Ohio).

I did come up with the latter name and address (Flerlage) in an old 1916 issue of Meekel's Stamp News as being a member of the APS, but certainly this booklet is more modern than that.

Thanks.