Spix, J. B. v., & Martius, C. F. P. v. (2013). Travels in Brazil in the years 1817 - 1820: Undertaken by command of His Majesty the King of Bavaria (Nachdr. d. Ausg. 1824.). Cambridge Univ. Press.
Chicago Style (17th ed.) CitationSpix, Johann Baptist von, and Carl Friedrich Philipp von Martius. Travels in Brazil in the Years 1817 - 1820: Undertaken by Command of His Majesty the King of Bavaria. Nachdr. d. Ausg. 1824. New York: Cambridge Univ. Press, 2013.
MLA (9th ed.) CitationSpix, Johann Baptist von, and Carl Friedrich Philipp von Martius. Travels in Brazil in the Years 1817 - 1820: Undertaken by Command of His Majesty the King of Bavaria. Nachdr. d. Ausg. 1824. Cambridge Univ. Press, 2013.
Warning: These citations may not always be 100% accurate.