1. E Posner. Derivations in prime rings, Proc Amer Math Soc, 1957, 8: 1093–1100.
2. G Georgescu, L Leuştean, V Preotesa. Pseudo hoops, J Mult Valued Log Soft Comput, 2005, 11: 153–184.
3. G Grätzer. Lattice theory, W H Freeman and Company, San Francisco, 1979.
4. H Masoud, M Mahboobeh. Folding theory applied to Rℓ-monoids, Annals of the University of Craiova, Mathematica and Computer Science Series, 2010, 37: 9–17.
5. J R Büchi, T M Owens. Complemented monoids and hoops, 1975, Unpublished manuscript.