Haq, Zahoor Ul; Meilke, Karl; Cranfield, John - In: European Review of Agricultural Economics 40 (2013) 2, pp. 331-360
In the analysis of bilateral trade flows, reported trade of zero or missing observations is quite common and this is a problem when estimating log-linear gravity equations. This has caused many researchers to either ignore the zero trade flows or replace the zero with a small positive number....
