A note on semi-pseudoorders in semigroups
N. Kehayopulu, M. Tsingelis

References
1.	N. Kehayopulu, M. Tsingelis, “On subdirectly irreducible ordered semigroups”, Semigroup Forum, 50 (1995), 161–177
2.	N. Kehayopulu, M. Tsingelis, “Pseudoorder in ordered semigroups”, Semigroup Forum, 50 (1995), 389–392
3.	N. Kehayopulu, M. Tsingelis, “A note on pseudocongruences in semigroups”, Lobachevskii J. Math., 11 (2002), 19–21