"Barbican". Metropolitan. Archived from the original on 1 May 2015. Retrieved 1 May 2015.
flickr.com
diamond, geezer (8 June 2013). "Barbican". flickr. Archived from the original on 1 May 2015. Retrieved 1 May 2015. "The disused signal box, the tunnels beneath Smithfield, and the future Crossrail entrance."
Lemmo (25 June 2012). "Fulsome Farringdon: Part 1". London Terminals. London Reconnections. Archived from the original on 17 March 2015. Retrieved 1 May 2015.
diamond, geezer (8 June 2013). "Barbican". flickr. Archived from the original on 1 May 2015. Retrieved 1 May 2015. "The disused signal box, the tunnels beneath Smithfield, and the future Crossrail entrance."
Lemmo (25 June 2012). "Fulsome Farringdon: Part 1". London Terminals. London Reconnections. Archived from the original on 17 March 2015. Retrieved 1 May 2015.
Feather, Clive. "Circle line". Clive's Underground Line Guides. Archived from the original on 1 May 2015. Retrieved 1 May 2015.
Feather, Clive. "Metropolitan line". Clive's Underground Line Guides. Archived from the original on 1 May 2015. Retrieved 1 May 2015.