@article{10_4153_CMB_2015_049_4,
     author = {Li, Chi-Kwong and Tsai, Ming-Cheng},
     title = {Factoring a {Quadratic} {Operator} as a {Product} of {Two} {Positive} {Contractions}},
     journal = {Canadian mathematical bulletin},
     pages = {354--362},
     year = {2016},
     volume = {59},
     number = {2},
     doi = {10.4153/CMB-2015-049-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2015-049-4/}
}