Studies and reviews:

Best site for purchasing pharmacology products - czystamasa.com

Testosterone Physiology - https://academic.oup.com/jcem/article/89/2/718/2840746

Stimulants - https://en.wikipedia.org/wiki/Stimulant

Beta-Alanine supplementation - https://pubmed.ncbi.nlm.nih.gov/32713327/