My own reconstruction of part of the Westminster Hall hammer-beam roof: http://thegolovine.wordpress.com/2013/11/
My PhD thesis: https://etheses.bham.ac.uk/id/eprint/5863/1/Beech15PhD_Final.pdf sadly without National Archives illustrations of Westminster Hall, so that chapter will be difficult to follow.
Archaeology Data Service: http://archaeologydataservice.ac.uk/archives/view/vag_dendro/
Ken's Great Barns: http://www.greatbarns.org.uk/
The Avoncroft Museum: http://www.avoncroft.org.uk/
Carpenters' Fellowship: http://www.carpentersfellowship.co.uk/
Orchard Barn traditional building skills: http://www.orchardbarn.org.uk/
Suffolk and Norfolk Churches: http://www.suffolkchurches.co.uk/
The Weald and Downland Museum: http://www.wealddown.co.uk/