Não informado. (1976). Quarterly oil statistics. Organization for Economic Co-operation and Development.
Citação do estilo Chicago (17ª ed.)Não informado. Quarterly Oil Statistics. Paris: Organization for Economic Co-operation and Development, 1976.
Citação MLA (8ª ed.)Não informado. Quarterly Oil Statistics. Organization for Economic Co-operation and Development, 1976.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.