MathSciDoc: An Archive for Mathematician ∫

@inproceedings{karl1960theory,
  title={Theory of$x$-ideals},
  author={Karl Egil Aubert},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203158247685931},
  booktitle={Acta Mathematica},
  volume={107},
  number={1},
  pages={1-52},
  year={1960},
}