Allcock et al. (1951), pp. 33, 35, 36. Allcock, N.J.; Davies, F.K.; le Fleming, H.M.; Maskelyne, J.N.; Reed, P.J.T.; Tabor, F.J. (June 1951). White, D.E. (ed.). The Locomotives of the Great Western Railway, part one: Preliminary Survey. Kenilworth: RCTS. ISBN0-901115-17-7. OCLC650412984. {{cite book}}: ISBN / Date incompatibility (help)