Multi‐Rate Sampled and Delayed Output Signal Prediction‐Based Observer Design for Two‐Stage Anaerobic Digestion Process. - Li, Hongxuan; Wang, Haoping; Tian, Yang; Zhuang, Xincheng; Kabaivanova, Lyudmila; Chorukova, Elena; Simeonov, Ivan; Christov, Nicolai (International Journal of Robust & Nonlinear Control, 2026)