Comments on "New general continuous-time state-task network formulation for short-term scheduling of multipurpose batch plants" by Christos T. Maravelias and Ignacio E. Grossmann and on "Enhanced continuous-time unit-specific event-based formulation for short-term scheduling of multipurpose batch processes: Resource constraints and mixed storage policies" by Stacy L. Janak, Xiaoxia Lin, and Christodoulos A. Floudas