@inproceedings{gregory2004the,
  title={The biharmonic Neumann problem in Lipschitz domains},
  author={Gregory C. Verchota},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203346852366666},
  booktitle={Acta Mathematica},
  volume={194},
  number={2},
  pages={217-279},
  year={2004},
}