Literature. Harris, L.J., Bargholtz, P., Paez T.R., 'Ecuador Postal History and a Listing of Prephilatelic Postmarks – Historia Postal y Catálogo de Marcas Prefilatélicas', The Collectors Club, New York, 1984, second edition, hardback, illustrated, xi + 35 + 98 pp., bilingual English and Spanish. Almost as new.
