Centro Vasco de Arquitectura
Euskal Herriko Arkitektura Ikerkundea
http://mx.depositphotos.com/13294622/stock-photo-paris-barriers.html
http://www.flickriver.com/photos/51366740@N07/sets/72157627041860074/
http://olga-totumrevolutum.blogspot.com.es/2012/10/utopicos-y-visionarios-la-arquitectura.html
https://commons.wikimedia.org/wiki/File:Paris-barri%C3%A8re_St_Martin_1800-11.jpg
http://urban-networks.blogspot.com.es/2013/11/el-paris-de-esnauts-y-rapilly-llevando.html
https://www.studyblue.com/notes/note/n/exam-3/deck/8661468