1. http://www.britannica.com/eb/article-9056655/Sergey-Vladimirovich-Obraztsov
2. http://www.jci.org/articles/view/115075
3. Garteveld V. I. Amidst loose sands and cut throats. Moscow, 1913
4. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2267438
5. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=2267438&blobname=nihms-37932-f0002.jpg
6. http://cat-sibiryak.ru/st-Sadovnikova1.htm