Portna, K. P., and S. O. Vasyuk. “β-Alanine Spectrophotometric Determination in Reaction With Sodium Salt of 1,2-Naphthoquinone-4-Sulfonic Acid”. Zaporozhye Medical Journal, vol. 17, no. 1, Feb. 2015, doi:10.14739/2310-1210.2015.1.39870.