International Perfume Museum, Grasse, France, Website: Archived copy // Архивиран от оригинала на 2007-06-24. Посетен на 2021-11-30.
doi.org
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Burdock, G. A. Safety assessment of castoreum extract as a food ingredient // International Journal of Toxicology 26 (1). 2007-01-01. DOI:10.1080/10915810601120145. с. 51 – 55. Шаблон:Free access
Burdock GA. Safety assessment of castoreum extract as a food ingredient // International Journal of Toxicology 26 (1). 2007. DOI:10.1080/10915810601120145. с. 51 – 5. Шаблон:Free access