Wilailak, N., Narkprasom, N., Tanongkankit, Y., Nookong, M., Sri-ngernyuang, C. and Narkprasom, K. 2025. Optimization for Lutein Extract and Antioxidant Activity from Marigold Flowers (𝙏𝙖𝙜𝙚𝙩𝙚𝙨 𝙚𝙧𝙚𝙘𝙩𝙖 L.) Using Ultrasonic Assisted Extraction. Burapha Science Journal. 30, 2 May-August (Jul. 2025), 597–613.