@inproceedings{michael1999optimal,
title={Optimal decompositions for the$K$-functional for a couple of Banach lattices},
author={Michael Cwikel, and Uri Keich},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203600552824760},
booktitle={Arkiv for Matematik},
volume={39},
number={1},
pages={27-64},
year={1999},
}

Michael Cwikel, and Uri Keich. Optimal decompositions for the$K$-functional for a couple of Banach lattices. 1999. Vol. 39. In Arkiv for Matematik. pp.27-64. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203600552824760.