Centro Vasco de Arquitectura
Euskal Herriko Arkitektura Ikerkundea
https://www.ushistory.org/birch/plates/plate19.htm
https://www.viator.com/Philadelphia-attractions/Library-Hall-American-Philosophical-Society-Museum/d906-a11344?
https://www.flickr.com/photos/sminor/34620107475
https://www.flickr.com/photos/sminor/34470142991/in/photostream/