Keharom, S.; Techawongstien, S.; Mahachai, R.; Chanthai, S. Analysis of Capsaicin and Dihydrocapsaicin from Sweet-to-Very Hot Chilli Peppers Using an Ultrasound-Assisted Extraction Followed by RP-HPLC-PDA. Asia Pac J Sci Technol 2015, 20, 54-65.