1. Arbib MA (1964) Brains, machines and mathematics. McGraw-Hill
2. Arena P, Fortuna L, Occhipinti L, Xibilia M (1994) Neural networks for quaternion-valued function approximation. In: Proceedings of IEEE international symposium on circuits and systems
3. Popa CA (2017) Learning algorithms for quaternion-valued neural networks. Neural Process Lett 47(2):1–25
4. Liu Y, Zhang D, Lou J, Lu J, Cao J (2018) Stability analysis of quaternion-valued neural networks: decomposition and direct approaches. IEEE Trans Neural Netw Learn Syst 29:4201–4210
5. Xia Y, Kou K, Liu Y (2021) Theory and applications of quaternion-valued differential equations. Science Press