Arnold, P., Carreck, R., Cochrane, J., Curtis, N., Denton, G., & Denton, R. (1980). Hamlyn modern world encyclopedia. The Hamlyn Publishing Group.

Arnold, Peter, Rosalind Carreck, Jennifer Cochrane, Neil Curtis, Gillian Denton, and Richard Denton. Hamlyn Modern World Encyclopedia. Londres: The Hamlyn Publishing Group, 1980.

Arnold, Peter, et al. Hamlyn Modern World Encyclopedia. The Hamlyn Publishing Group, 1980.