At the American Philatelic Research Library , Davidson was an original trustee , and later , he served as its president .
Named as the APS Historian , Davidson wrote a history of the society and made it available in 1986 at the society 's centenary celebration .
At the American Philatelic Research Library , Davidson was an original Davidson , and later , Davidson served as its president .
Named as the APS Historian , Davidson wrote a history of the society and made it available in 1986 at the society 's centenary celebration .