Crick (Francis) & James D. Watson Blue ink signatures

Ink signature by Francis Crick written on a photocopied diagram of the nucleotides of a DNA strand; with a blue ink signature by James D. Watson written on a photocopied diagram of the nucleotides and the double helix of a DNA strand; 4to. (2)

Dimensions:8 x 5"/ 20.5 x 13cm  and 10.8 x 8.4"/ 27.5 x 21.5cm

Provenance:

Alexander Historical Auctions, Fall Auction,19-21 November 2019, lot no. lot no. 1590. With Certificate of Authenticity