[1] K. L. N. Swamy: Dually residuated lattice ordered semigroups. Math. Ann. 159 (1965), 105-114. DOI 10.1007/BF01360284 | MR 0183797 | Zbl 0138.02104

[2] K. L. N. Swamy N. P. Rao: Ideals in autometrized algebras. J. Austral. Math. Soc. (Ser. A) 24 (1977), 362-374. DOI 10.1017/S1446788700020383 | MR 0469843

[3] K. L. N. Swamy B. V. Subba Rao: Isometries in dually residuated lattice ordered semigroups. Math. Sem. Notes 8 (1980), 369-380. MR 0601906