This lot is closed for bidding. Bidding ended on 5/29/2015
''Jonas Salk'' signs a commemorative first day cover as the inventor of the first effective vaccine against polio. His colleague ''Albert B. Sabin'' also signs. The cover honors Dr. George Papanicolaou, developer of the Pap test for early cancer detection. Postmarked 18 May 1978, it measures 6.5'' x 3.75''. Near fine.