Media type: E-Article Title: Conditional Covariance Theory and Detect for Polytomous Items Contributor: Zhang, Jinming imprint: Springer Science and Business Media LLC, 2007 Published in: Psychometrika Language: English DOI: 10.1007/s11336-004-1257-7 ISSN: 1860-0980; 0033-3123 Keywords: Applied Mathematics ; General Psychology Origination: Footnote: