1. Perfecto simple y compuesto en español;Alarcos Llorach;Revista de Filologia Española,1947
2. An essay concerning aspect;Anderson,1973
3. How children talk about what happened;Antinucci;Journal of Child Language,1976
4. Formal semantics for verb tenses as analyzed by Reichenbach;Åqvist,1976
5. Clitic inflection in French;Ashby,1977