References
- M. Kilp, U. Knauer and A. V. Mikhalev, Monoids, Acts and Categories, With Application to Wreath Product, Berlin; New York, 2000.
- X. Zhang, U. Knauer and Y. Chen, Classification of monoids by injectivities I. C-injectivity, Semigroup Forum, 76 (2008), 169-176. https://doi.org/10.1007/s00233-007-9022-8