Nichols, Herbert L.
Moving the earth : the workbook of excavation
McGraw-Hill, 1976
 Buku Referensi
Turner, Joe M.
Excavation systems: planning, design, and safety
McGraw-Hill, 2009
 Buku Teks
Church, Horace K.
Excavation handbook
McGraw-Hill, 1981
 Buku Referensi
Nichols, Herbert L.
Moving the earth: the workbook of excavation
McGraw-Hill, 2010
 Buku Teks
An Outline of American History
Office of International Information Programs, 1991
 Buku Teks SO