M. A. A. A. Alwaeel, N. Mohammed Juma, N. Ansari, N. Singhb, and L. Nader, “Impact of Temperature, Storage Duration, and Preservative Addition on the Stability of Tramadol in Urine Samples”, Int J Med Toxicol Forensic Med, vol. 16, pp. 1–15, Jan. 2026.