20th century inventions /

Eitemau Tebyg

• Discoveries and inventions of the 20th century.
  gan: Crowther, J. G. (James Gerald), 1899-
  Cyhoeddwyd: (1966)
• Inventions in the century,
  gan: Doolittle, William Henry, 1844-
  Cyhoeddwyd: (1903)
• Discoveries and inventions of the twentieth century /
  gan: Cressy, Edward
  Cyhoeddwyd: (1930)
• Eighteenth century inventions
  gan: Rowland, K. T.
  Cyhoeddwyd: (1974)
• The sources of invention /
  gan: Jewkes, John, 1902-
  Cyhoeddwyd: (1958)