@inproceedings{stevo1986partitioning,
title={Partitioning pairs of countable ordinals},
author={Stevo Todorcevic},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203309328605408},
booktitle={Acta Mathematica},
volume={159},
number={1},
pages={261-294},
year={1986},
}