K Sijtsma

A survey of theory and methods of invariant item ordering.

K Sijtsma, B W Junker, B. Junker, 1996, The British journal of mathematical and statistical psychology.

Influence of Imputation and EM Methods on Factor Analysis when Item Nonresponse in Questionnaire Data is Nonignorable

K Sijtsma, K. Sijtsma, C. Bernaards, 2000, Multivariate behavioral research.