M. Rahardjo, M. Sihombing, and B. M. A. Wulandari, “Physical and sensory characteristics of sourdough bread enriched with beetroot (Beta vulgaris L.) powder”, J. Trop. AgriFood., vol. 8, no. 5, pp. 20–34, Apr. 2026, doi: 10.35941/jtaf.8.5.2026.26714.20-34.