“ON THE GRAY-HERVELLA CLASSES OF AH-STRUCTURES ON SIX-DIMENSIONAL SUBMANIFOLDS OF CAYLEY ALGEBRA”, Ann. Sofia Univ. Fac. Math. and Inf., vol. 95, pp. 125–131, Dec. 2003, Accessed: Dec. 14, 2025. [Online]. Available: https://annual.uni-sofia.bg/index.php/fmi/article/view/182