f Modern Geography: 2. William Blackwood. 1870. pp. 18– – via Google Books.↑ Dunn, Ross E.; Mitchell, Laura J.; Ward, Kerry (23 August 2016). The New World History: A Field Guide for Teachers and Researchers. University of California Press. pp. 232–. ISBN 978-0-520-28989-5 – via Google Books.↑ Chatterjee, Sankar (13 March 2015). The Rise of Birds: 225 Million Years of Evolution. Johns Hopkins University Press. pp. 204–. ISBN 978-1-4214-1614-4 – via Google Books.↑ Mackay, Alexander (1861). Manual of Modern Geography: Mathematical, Physical, and Political : on a New Plan : Embracing a Complete Development of the River Systems of the Globe. W. Blackwood and Sons. pp. 15–.↑ Kermack, D. M. (9 March 2013). The Evolution of Mammalian Characters. Springer Science+Business Media. pp. 141–. ISBN 978-1-4684-7817-4 – via Google Books.↑ [2] "In some textbooks, North and South America are combined into "America" and/or Europe and Asia are combined into "Eurasia", for a grant total of 6 or 