Muir, Robert
Henry Frowde, Hodder & Stoughton, 1921
Buku Teks SO
edited by Kenneth R. Niswander
Litle, Brown, 1983
Buku Teks SO
Browning, Carl H.
Oxford University Press, 1937
Buku Referensi
Markus, John, 1911-
McGraw-Hill, 1971
Buku Referensi
Box, Paul C.
Institut of Transportation Engineers, 1976
Buku Referensi