18.Phlebology: A Systematic Review of Compression Hosiery for Uncomplicated Varicose Veins, www.rsm.ac.uk/academ/downloads/vein1_3.pdf
19.Medline Plus: Horse Chestnut, www.nlm.nih.gov/medlineplus/druginfo/natural/1055.html
20.University of Maryland Medical Center: Grape Seed, www.umn.edu/altmed/articles/grape-seed-000254.htm
21.MedlinePlus: Pycnogenol, www.nlm.nih.gov/medlineplus/druginfo/natural/1019.html