[[1] Grzegorz Bancerek. The ordinal numbers. Formalized Mathematics, 1(1):91-96, 1990.]Search in Google Scholar
[[2] Yuzhong Ding. Several classes of BCI-algebras and their properties. Formalized Mathematics, 15(1):1-9, 2007.10.2478/v10037-007-0001-z]Search in Google Scholar
[[3] Yuzhong Ding and Zhiyong Pang. Congruences and quotient algebras of BCI-algebras. Formalized Mathematics, 15(4):175-180, 2007.10.2478/v10037-007-0021-8]Search in Google Scholar
[[4] Jie Meng and YoungLin Liu. An Introduction to BCI-algebras. Shaanxi Scientific and Technological Press, 2001.]Search in Google Scholar
[[5] Tao Sun, Dahai Hu, and Xiquan Liang. Several classes of BCK-algebras and their properties. Formalized Mathematics, 15(4):237-242, 2007.10.2478/v10037-007-0027-2]Search in Google Scholar
[[6] Andrzej Trybulec and Agata Darmochwał. Boolean domains. Formalized Mathematics, 1(1):187-190, 1990.]Search in Google Scholar
[[7] Zinaida Trybulec. Properties of subsets. Formalized Mathematics, 1(1):67-71, 1990.]Search in Google Scholar