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22) N Demirkol, M Yetmez, U Karacayli, ES Kayali, O Gunduz, S Agathopoulos, FN Oktar, "Mechanical properties of bovine enamel derived hydroxyapatite", The International Journal of Artificial Organs.

21) FN Oktar, U Tuyel, N Demirkol, O Gunduz, R Samur, S Kannan, S Agathopoulos, "A new safe method to produce bioceramic nano-powders from nacre venus verrucosa", The International Journal of Artificial Organs.