1. The acquisition of negation;Bellugi,1967
2. Language development: Form and function in emerging grammars;Bloom,1970
3. On children's interpretation of negation;de Boysson-Bardies;Journal of Experimental Child Psychology,1977
4. Some facts one simply cannot deny;de Villiers;Journal of Child Language,1975
5. Developmental aspects of performance with negatives;Donaldson,1970