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5. https://www.cbsnews.com/news/5-things-you-didnt-know-about-your-penis/

6. Biomed Research International (2014). Alga Ecklonia bicyclis, Tribulus terrestris, and glucosamine oligosaccharide improve erectile function, sexual quality of life, and ejaculation function in patients with moderate mild-moderate erectile dysfunction: a prospective, randomized, placebo-controlled, single-blinded study. Sansalone S, Leonardi R, Antonini G, Vitarelli A, Vespasiani G, Basic D, Morgia G, Cimino S, Russo GI. https://www.hindawi.com/journals/bmri/2014/121396/

7. AYU (2012). Clinical study of Tribulus terrestris Linn. in Oligozoospermia: A double blind study. Sellandi TM, Thakar AB, Baghel MS. https://www.ncbi.nlm.nih.gov/pubmed/23723641

8. https://www.globalhealingcenter.com/natural-health/benefits-of-catuaba-bark/

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