Popular cyclopaedia of life science /

Eitemau Tebyg

• Pears Cyclopaedia
  Cyhoeddwyd: (1897)
• Pears cyclopaedia : a book of background information and reference for everyday use /
• Pears cyclopaedia [1971-1972]: book of background information and reference for everyday use /
  Cyhoeddwyd: (1971)
• Book of popular science, Vol.1
  Cyhoeddwyd: (1976)
• Book of popular science, Vol.2
  Cyhoeddwyd: (1976)