Noll, A Short History of Mexico (Chicago, 1903); Santiago Ramirez, Noticia historica de la riqueza mineira de Mexico (Mexico, 1884); Friedrich Ratzel, Aus Mexico: Reiseskizzen aus den Jahren 1874-1876 (Breslau, 1878); Matias Romero, Geographical and Statistical Notes on Mexico (New York, 1898); idem, Mexico and the United States (New York, 1898); E.