Metrically regular bigraphs the square of which are metrically regular graphs are investigated in the case of graphs with 6 distinct eigenvalues (these eigenvalues can have variuos multiplicities).
@article{107432,
author = {Vladim\'\i r Vetch\'y},
title = {Metrically regular square of metrically regular bigraphs. II.},
journal = {Archivum Mathematicum},
volume = {028},
year = {1992},
pages = {17-24},
zbl = {0778.05058},
mrnumber = {1201862},
language = {en},
url = {http://dml.mathdoc.fr/item/107432}
}
Vetchý, Vladimír. Metrically regular square of metrically regular bigraphs. II.. Archivum Mathematicum, Tome 028 (1992) pp. 17-24. http://gdmltest.u-ga.fr/item/107432/
Association Schemes I, Arch. Math. (Brno) 17 (1981), 173-184. (1981) | MR 0672657 | Zbl 0479.05020
Metrically regular square of metrically regular bigraphs I, Arch. Math. (Brno), Tomus 27b (1992), 183-197. (1992) | MR 1189214