- 
              
            911
- 
              
            912
- 
              
            913
- 
              
            914
- 
              
            915
- 
              
            916The use of two dimensional chart in test constructionGepubliceerd in Education Quarterly (1958)Artikel
- 
              
            917
- 
              
            918
- 
              
            919
- 
              
            920