Giacomo Lenzi. On a positive set theory with inequality. Math. Log. Q., 57(5):474-480, 2011. [doi]
@article{Lenzi11, title = {On a positive set theory with inequality}, author = {Giacomo Lenzi}, year = {2011}, doi = {10.1002/malq.201010022}, url = {http://dx.doi.org/10.1002/malq.201010022}, researchr = {https://researchr.org/publication/Lenzi11}, cites = {0}, citedby = {0}, journal = {Math. Log. Q.}, volume = {57}, number = {5}, pages = {474-480}, }