%0 Journal Article %T Item Parameter Estimation Via Marginal Maximum Likelihood and an EM Algorithm: A Didactic %A Harwell, Michael R. %A Baker, Frank B. %A Zwarts, Michael %J Journal of Educational Statistics %V 13 %N 3 %P 243-271 %@ 0362-9791 %D 1988-09-01 %I SAGE Publications %~ DeepDyve