(March 2018) Renumbered from OAImages and Blue Book; S18.5 is now S19; other flaps renumbered in correct issuing sequence.
(April 2020): Neckerchiefs have been renumbered. Fundamentally all the N9-N15 neckerchiefs were derived from the same Decal/Screenprint pattern and applied to neckerchiefs of varying composition. At the time the Blue Book editors classified all of these as new issues/discoveries and created a lot more issues than necessary. 50th Anniversary NCs are being renumbered to reflect a smaller number of varieties.