[1] J. Duplák: Quasigroups determined by balanced identities of length $\leq 6$. Czech. Math. J. 36, 1986, 599-616. MR 0863190

[2] J. Ježek, T. Kepka: Varieties of quasigroups determined by short strictly balanced identities. Czech. Math. J. 29, 1979, 84-96. MR 0518142

[3] J. Ježek, T. Kepka: Medial groupoids. Rozpravy ČSAV, Řada Mat. a Přír. Věd. 93/1, 1983, Academia, Praha. MR 0734873

[4] J. Ježek, T. Kepka: Permutable groupoids. Czech. Math. J. 34, 1984, 396-410. MR 0761422

[5] J. Ježek, T. Kepka: Modular groupoids. Czech. Math. J. 34, 1984, 477-487. MR 0761429