Walker, Walter Frederick - The Azores : or Western Islands, a political, commercial and geographical account, containing what is historically known of these islands, and descriptive of their scenery, inhabitants, and natural productions; having special reference to the eastern group consisting of St. Michael and St. Mary, The Formigas and Dollabaret Rocks; incluinding suggestions to travellers and invalids who may resort to the archipelago in search of health, London, Trubner & Co, 1886.
