Walker, T. A. (1969). The Severn Tunnel: Its construction and difficulties, 1872-1887 (3rd ed. [reprinted].). Kingsmead Reprints.
Chicago-Zitierstil (17. Ausg.)Walker, Thomas Andrew. The Severn Tunnel: Its Construction and Difficulties, 1872-1887. 3rd ed. [reprinted]. Bath: Kingsmead Reprints, 1969.
MLA-Zitierstil (8. Ausg.)Walker, Thomas Andrew. The Severn Tunnel: Its Construction and Difficulties, 1872-1887. 3rd ed. [reprinted]. Kingsmead Reprints, 1969.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.