Encyclopaedia of occupational health and safety /

Eitemau Tebyg

• The Encyclopedia Americana : the international reference work /
  Cyhoeddwyd: (1961)
• The Encyclopedia Americana : the international reference work /
  Cyhoeddwyd: (1961)
• McGraw-Hill encyclopedia of environmental science.
  Cyhoeddwyd: (1974)
• technical dictionary of data processing, computers and office machines : four - language.
  gan: burger, erich
  Cyhoeddwyd: (1970)
• The Dictionary of Economics and Commerce : Z. Naser.
  gan: .Nasr, Z.
  Cyhoeddwyd: (1979)