Khattab, M. Q.; Tributsch, H. (2015). „Fibre-optical light scattering technology in polar bear hair: A re-evaluation and new results“. Journal of Advanced Biotechnology and Bioengineering. 3 (2): 38–51. doi:10.12970/2311-1755.2015.03.02.2. ISSN2311-1755.
Khattab, M. Q.; Tributsch, H. (2015). „Fibre-optical light scattering technology in polar bear hair: A re-evaluation and new results“. Journal of Advanced Biotechnology and Bioengineering. 3 (2): 38–51. doi:10.12970/2311-1755.2015.03.02.2. ISSN2311-1755.