@article{oai:oist.repo.nii.ac.jp:00002192,
 author = {Wilken, Gunnar},
 issue = {9},
 journal = {Annals of Pure and Applied Logic},
 month = {May},
 note = {We display the entire structure R-2 coding Sigma(1) - and Sigma(2)-elementarity on the ordinals. This will enable the analysis of pure Sigma(3)-elementary substructures.},
 title = {Pure Σ2-elementarity beyond the core},
 volume = {172},
 year = {2021}
}