Despite the presence of structure, interactions between the three views on VLSI design still lead to lengthy iterations. By separating the hierarchies for the respective views, the interactions are reduced. This separated hierarchy allows top-down design with functional abstractions as exemplified by an experimental self-timed CMOS RISC computer design.
Spaanenburg, L., Broekema, A., Leenstra, J., & Huys, C. (1986). VLSI top-down design based on the separation of hierarchies. Microprocessing and Microprogramming, 18(1-5), 341-346. https://doi.org/10.1016/0165-6074(86)90062-1