APA Citation

 Krugman, P. R. (2015).  International economics: Theory and policy.  Pearson.

Chicago Style Citation

 Krugman, Paul R.  International Economics: Theory and Policy.  Pearson, 2015.

MLA Citation

 Krugman, Paul R.  International Economics: Theory and Policy.  Pearson, 2015.

Warning: These citations may not always be 100% accurate.