http://www.jstor.org/pss/2950973
The Case of the Missing Trade and Other Mysteries Daniel Trefler The American Economic Review, Vol. 85, No. 5 (Dec., 1995), pp. 1029-1046
http://www.jstor.org/pss/3083342
The Case of the Missing Trade and Other Mysteries: Comment Patrick J. Conway The American Economic Review, Vol. 92, No. 1 (Mar., 2002), pp. 394-404
(article consists of 11 pages)