Nichols Sandra. Why Was Humboldt Forgotten in the United States? // Geographical Review, vol. 96, 2006.

Nicolai Friedrich. Beschreibung der Königlichen Residenzstädte Berlin und Potsdam und aller daselbst befindlicher Merkwürdigkeiten, Berlin: Buchhändler unter der Stechbahn, 1769.

Nollendorf Cora Lee. Alexander von Humboldt Centennial Celebrations in the United States: Controversies Concerning his Work // Monatshefte, vol. 80, 1988.

North Douglass C. Growth and Welfare in the American Past. Englewood Cliffs: Prentice-Hall International, 1974.

Norton Paul F. Thomas Jefferson and the Planning of the National Capital // Jefferson and the Arts: An Extended View. William Howard Adams (ed.). Washington, DC: National Gallery of Art, 1976.

O’Hara James Gabriel. Gauss and the Royal Society: The Reception of his Ideas on Magnetism in Britain (1832–1842) // Notes and Records of the Royal Society of London, vol. 38, 1983.

O’Leary Daniel F. Memorias del General O’Leary. Caracas: Imprenta de El Monitor, 1879–1888.

______. Bolívar y la emancipación de Sur-America. Madrid: Sociedad Española de Librería, 1915.

______. The ‘Detached Recollections’ of General D. F. O’Leary. R. A. Humphreys (ed.). London: Published for the Institute of Latin American Studies, Athlone Press, 1969.

Oppitz Ulrich-Dieter. Der Name der Brüder Humboldt in aller Welt // Alexander von Humboldt. Werk und Weltgeltung. Heinrich von Pfeiffer (eds.). München: Pieper, 1969.

Osten Manfred. Der See von Valencia oder Alexander von Humboldt als Pionier der Umweltbewegung // Schnittpunkt Slavistik. Ost und West im Wissenschaftlichem Dialog. Irina Podterga (ed.). Bonn: University Press, vol. 1, 2012.

Päßler Ulrich. Ein ‘Diplomat aus den Wäldern des Orinoko’. Alexander von Humboldt als Mittler zwischen Preußen und Frankreich. Stuttgart: Steiner Verlag, 2009.

Patterson Elizabeth C. Mary Somerville // The British Journal for the History of Science, vol. 4, 1969.

______. The Case of Mary Somerville: An Aspect of Nineteenth-Century Science // Proceedings of the American Philosophical Society, vol. 118, 1975.

Peale Charles Willson. The Selected Papers of Charles Willson Peale and His Family. Lillian B. Miller (ed.). New Haven and London: Yale University Press, 1983–2000.

Pfeiffer Heinrich von (ed.). Alexander von Humboldt. Werk und Weltgeltung. München: Pieper, 1969.

Phillips Denise. Building Humboldt’s Legacy: The Humboldt Memorials of 1869 in Germany // Northeastern Naturalist, vol. 8, 2001.

Pieper Herbert. Alexander von Humboldt: Die Geognosie der Vulkane // HiN VII, vol. 13, 2006.

Plumer William. William Plumer’s Memorandum of Proceedings in the United States Senate 1803–1807. Everett Somerville Brown (ed.). New York: Macmillan Company, 1923.

Podach Erich Friedrich. Alexander von Humboldt in Paris: Urkunden und Begebnisse // Alexander von Humboldt: Studien zu seiner universalen Geisteshaltung. Joachim Schultze (ed.). Berlin: Walter de Gruyter, 1959.

Poe Edgar Allan. Eureka. A Prose Poem. New York: Putnam, 1848.

Porter Roy (ed.). Cambridge History of Science. Eighteenth-Century Science. Cambridge: Cambridge University Press, vol. 4, 2003.

Pratt Marie Louise. Imperial Eyes. Travel Writing and Transculturation. London: Routledge, 1992.

Proctor Robert. Architecture from the Cell-Soul: Rene Binet and Ernst Haeckel // Journal of Architecture, vol. 11, 2006.

Pückler Muskau, Hermann Prince of, Tour in England, Ireland and France, in the Years 1826, 1827, 1828 and 1829, Philadelphia: Carey, Lea and Blanchard, 1833.

Pudney John. Brunel and his World. London: Thames and Hudson, 1974.

Puig-Samper Miguel-Ángel and Sandra Rebok. Charles Darwin and Alexander von Humboldt: An Exchange of Looks between Famous Naturalists // HiN XI, vol. 21, 2010.

Rebok Sandra. Two Exponents of the Enlightenment: Transatlantic Communication by Thomas Jefferson and Alexander von Humboldt // Southern Quarterly, vol. 43, no. 4, 2006.

______. Humboldt and Jefferson: A Transatlantic Friendship of the Enlightenment. Charlottesville: University of Virginia Press, 2014.

Recke Elisa von der. Tagebuch einer Reise durch einen Theil Deutschlands und durch Italien in den Jahren 1804 bis 1806. Carl August Böttiger (ed.). Berlin: In der Nicolaischen Buchhandlung, 1815.

Reill Peter Hanns. The Legacy of the “Scientific Revolution”. Science and the Enlightenment // Cambridge History of Science. Eighteenth-Century Science. Roy Porter (ed.). Cambridge: Cambridge University Press, vol. 4, 2003.

Richards Robert J. The Romantic Conception of Life: Science and Philosophy in the Age of Goethe. Chicago and London: Chicago University Press, 2002.

______. The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought. Chicago and London: University of Chicago Press, 2009.

Richardson Heather Cox. West from Appomattox. The Reconstruction of America after the Civil War. New Haven and London: Yale University Press, 2007.

Richardson Robert D. Henry Thoreau. A Life of the Mind. Berkeley: University of California Press, 1986.

Rippy Fred J. and E. R. Brann. Alexander von Humboldt and Simón Bolívar // American Historical Review, vol. 52, 1947.

Robinson Henry Crabb. Diary, Reminiscences, and Correspondence of Henry Crabb Robinson. Thomas Sadler (ed.). London: Macmillan and Co., 1869.

Rodríguez José Ángel. Alexander von Humboldt y la Independencia de Venezuela // Humboldt y la Emancipación de Hispanoamérica. Segundo E. Moreno Yánez (ed.). Quito: Edipuce, 2011.

Roe Shirley A. The Life Sciences // Cambridge History of Science. Eighteenth-Century Science. Roy Porter (ed.). Cambridge: Cambridge University Press, vol. 4, 2003.

Rose Gustav. Mineralogisch-Geognostische Reise nach dem Ural, dem Altai und dem Kaspischen Meere. Berlin: Verlag der Sanderschen Buchhandlung, 1837–1842.

Rossi William (ed.). Walden; and, Resistance to Civil Government: Authoritative Texts, Thoreau’s Journal, Reviews and Essays in Criticism. New York and London: Norton, 1992.

Roussanova Elena. Hermann Trautschold und die Ehrung, Alexander von Humboldts in Russland // HiN XIV, vol. 27, 2013.

Rudwick Martin J. S. The New Science of Geology: Studies in the Earth Sciences in the Age of Revolution. Aldershot: Ashgate Variorum, 2004.