Bibliography (8):

1. A meta-analysis of the correlations among broad intelligences: Understanding their relations

2. Genetic and Environmental Influences on the Development of Piagetian Logico-Mathematical Concepts and Other Specific Cognitive Abilities: A Twin Study

3. Beyond individual intelligence tests: Application of Cattell-Horn-Carroll Theory

4. Wikipedia Bibliography:

   1. Structural equation modeling

   2. Meta-analysis

   3. Piaget's theory of cognitive development

   4. https://en.wikipedia.org/wiki/Concurrent_validity  :

      https://en.wikipedia.org/wiki/Concurrent_validity

   5. https://en.wikipedia.org/wiki/Confirmatory_factor_analysis  :

      https://en.wikipedia.org/wiki/Confirmatory_factor_analysis