Mansfield, Edward D. (March 1993). "Concentration, Polarity, and the Distribution of Power". International Studies Quarterly. Blackwell Publishing. 37 (1): 105–128. doi:10.2307/2600833. JSTOR2600833.Parameter |access-date= membutuhkan |url= (bantuan)
jstor.org
Mansfield, Edward D. (March 1993). "Concentration, Polarity, and the Distribution of Power". International Studies Quarterly. Blackwell Publishing. 37 (1): 105–128. doi:10.2307/2600833. JSTOR2600833.Parameter |access-date= membutuhkan |url= (bantuan)