^Peach, B. N.; et al. The Geological Structure of the North-West Highlands of Scotland. Memoirs of the Geological Survey of Great Britain, Scotland. Glasgow: H.M.S.O.
^Oldroyd, David R. (1990). The Highlands Controversy: Constructing Geological Knowledge through Fieldwork in Nineteenth-Century Britain. University of Chicago Press. ISBN978-0-226-62634-5.
^"Tarbuttite"(PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 2012-07-19.
^Georgano, G.N. (1985). Cars: Early and Vintage, 1886–1930. London: Grange-Universal.
^"Hagenbeck Tierpark und Tropen-Aquarium". Zoo and Aquarium Visitor. Archived from the original on 2009-12-21. Retrieved 2008-07-22. The founder and his idea Carl Hagenbeck built what no other dared dream of. In 1907, the Hamburg man opened the first barless zoo in the world. As early as the end of the 19th century, this son of a fishmonger had the idea of showing animals no longer caged up but in open viewing enclosures. In his zoo of the future, nothing more than unseen ditches were to separate wild animals from members of the public. Carl Hagenbeck patented this idea in 1896. Nine years later his dream was to come true in Hamburg-Stellingen. The revolutionary open viewing enclosures and panoramas were in fact ridiculed in professional circles but took the public's breath away. Hagenbeck's zoo is considered to have prepared the way for today's wildlife adventure parks.
^Rothfels, Nigel (2002). Savages and Beasts: The Birth of the Modern Zoo. Baltimore: Johns Hopkins University Press. ISBN0-8018-6910-2.
^Haines, Catharine M C; Stevens, Helen M (2001). International Women in Science: A Biographical Dictionary to 1950. Santa Barbara: ABC-CLIO. p. 66. ISBN978-1-57607-090-1.
