Ewen, David
The complete book of 20th century music
Prentice-Hall, 1952
 Buku Teks
Li, Lanqing
Biographies and notes : Chinese music 20th century and beyond
Gale Asia, 2009
 Buku Teks
Carlson, Paul A.
20th century bookkeeping & accounting
South Western, 1957
 Buku Teks
Freud and the 20th century
edited and selected by Benjamin Nelson
George Allen and Unwin, 1958
 Buku Teks
Berle, Adolf A., Jr.
The 20th century capitalist revolution
Harcourt, Brace, 1954
 Buku Klasik