NOBEL WINNERS AND SCIENTISTS Fine lot of 16 first day or commemorative postal covers signed by notable scientists, including: BENJAMIN SPOCK (2), ALBERT SABIN (2), JONAS SALK (2), J. MICHAEL BISHOP (2), WERNER AXBEC, S. E. LAURIA, MICHAEL S. BROWN, ADRIAN KANTROWITZ, KARL MENNINGER, PAUL FLOREY, CHRISTIAN BARNARD, and MICHAEL DE BAKEY. Very good.