@article{
    PNMFAFIP,
    author = "Zhirong Yang, Zhijian Yuan and Laaksonen, Jorma",
    title = "Projective Nonnegative Matrix Factorization with Applications to Facial Image Processing",
    timestamp = "2008.12.01",
    journal = "International Journal on Pattern Recognition \& Artificial Intelligence",
    number = "8",
    volume = "21",
    year = "2007",
    flaggs = "copy",
    pages = "1353-1362"
}