Photogram no.2 George Smyth (2009) Source: Flickr Licence: CC BY-NC-SA 2.0
George Bill Domonkos (2014) Source: Public Domain Review/Library of Congress Licence: CC BY-SA 2.0
Photo-micrographs Arthur E Smith (1909) Source: Public Domain Review/Flickr Licence: CC BY 2.0
