 መሣሪያ ተለዋዋጮች መግቢያ ለማግኘት ተመልከት Angrist and Pischke (2009) (ያነሰ መደበኛ) ወይም Angrist, Imbens, and Rubin (1996) (በተጨማሪ መደበኛ).
Fun ohun ifihan to repo oniyipada ri Angrist and Pischke (2009) (kere lodo) tabi Angrist, Imbens, and Rubin (1996) (diẹ lodo).