1. I. Aguiló, J. Martín, G. Mayor, J. Suñer, and O. Valero, Smallest enclosing ball multidistance, Commun. Inf. Syst., 12 (2012), 185–194
2. M. M. Deza and E. Deza, Encyclopedia of Distances, third edition, Springer (2014).
3. Dhage, B.C.: Generalised metric spaces and mappings with fixed point. Bull. Calcutta Math. Soc. 84, 329–336 (1992)
4. G. Kiss, J.-L. Marichal, and B. Teheux, An extension of the concept of distance as functions of several variables, in: Proc. 36th Linz Seminar on Fuzzy Set Theory (LINZ 2016), Linz, Austria, Feb. 2–6, 2016, pp. 53–56
5. Kiss, G., Marichal, J.-L., Teheux, B.: A generalization of the concept of distance based on the simplex inequality. Beitr. Algebra Geom. 59, 247–266 (2018)