.Bunge, M. (2009). Causality and modern science (4th ed). New Brunswick, N.J. USA: Transaction Publishers
.Pearl Pearl , J. (2009). , J. (2009). Causality: models, reasoning and inference (2nd ed.). Cambridge, UK: Cambridge University ed.).
• Rigdon Rigdon Rigdon, E. (1995). A necessary and sufficient , identification rule for structural models estimated in identification rule for structural models estimated in practice. Multivariate Behavioral Behavioral Behavioral Research Research , 30 (3), 359 (3), 359 (3), 359 – 383