http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Tunnel shields and the use of compressed air in subaqueous works
1 online resource (xv, 389 pages) : illustrations.
At the time of writing, virtually nothing had been published on the history of shield-work - the employment of a shield, with or without the aid of compressed air, in tunnelling operations of English origin. The author's aim was to gather in one volume a mass of information until then scattered and difficult to find.