Junnu, S. , Srisawat, C. , Jantarapassvorn, S., Soi-ampornkul, R. , Wattanaraksakul, N. and Neungton, N. 2005. Comparative Study of Two Screening Tests for Urinary Porphyrins in the Diagnosis of Porphyrias. Siriraj Medical Journal. 57, 12 (Dec. 2005), 531–536.