German chemist Martin Klaproth Heinrich discovered a number of elements in the 19th century, including uranium and zirconium.
Martin Heinrich Klaproth. (2013). The Biography Channel website. Retrieved 01:10, May 18, 2013, from http://www.biography.com/people/martin-heinrich-klaproth-9366254.
Martin Heinrich Klaproth. [Internet]. 2013. The Biography Channel website. Available from: http://www.biography.com/people/martin-heinrich-klaproth-9366254 [Accessed 18 May 2013].
"Martin Heinrich Klaproth." 2013. The Biography Channel website. May 18 2013, 01:10 http://www.biography.com/people/martin-heinrich-klaproth-9366254.
"Martin Heinrich Klaproth," The Biography Channel website, 2013, http://www.biography.com/people/martin-heinrich-klaproth-9366254 [accessed May 18, 2013].
"Martin Heinrich Klaproth," The Biography Channel website, http://www.biography.com/people/martin-heinrich-klaproth-9366254 (accessed May 18, 2013).
Martin Heinrich Klaproth [Internet]. The Biography Channel website; 2013 [cited 2013 May 18] Available from: http://www.biography.com/people/martin-heinrich-klaproth-9366254.
Martin Heinrich Klaproth, http://www.biography.com/people/martin-heinrich-klaproth-9366254 (last visited May 18, 2013).
Martin Heinrich Klaproth. The Biography Channel website. 2013. Available at: http://www.biography.com/people/martin-heinrich-klaproth-9366254. Accessed May 18, 2013.