Crittenden, John C., author
John Wiley & Sons, 2012
Buku Teks
compiled by Michael and Irene Ash
Gower, 1996
Buku Referensi
Smethrust, George
Thomas Telford, 1997
Buku Teks
Tebbutt, T.H.Y.
Pergamon Press, 1983
Buku Teks
edited by Frank N. Kemmer
McGraw-Hill, 2009
Buku Referensi