The 4 linked references in paper Maggie X. Chen, Aaditya Mattoo (2008) “Regionalism in Standards: Good or Bad for Trade?” / RePEc:gwi:wpaper:2009-14

  1. Anderson, James E. (1979) ëA theoretical foundation for the gravity equation.íAmerican
  2. University Press)
  3. Michigan Press)
  4. The UK experience.íEconomic Journal106, 1297ñ1313