@article{Cia-2013,
    author={Patrick Ciarlet },
    title={Analysis of the Scott-Zhang interpolation in the fractional 
           order Sobolev spaces },
    doi={10.1515/jnum-2013-0007 },
    journal={J. Numer. Math. },
    year={2013 },
    volume={21 },
    pages={173--180},
}