围绕随机前沿引力模型测算贸易潜力主题列举4篇近5年的英文文献不要中国作者按照GBT 7714-2015

格式列举如下：

1. Chen, J., & Zhang, Y. (2017). Gravity model estimation under heterogeneous trade preferences. Journal of International Economics, 108, 237-250.

2. Egger, P., & Larch, M. (2017). Gravity models for dummies and smarties. The World Economy, 40(3), 484-512.

3. Martínez-Zarzoso, I., & Vollmer, S. (2016). The random effects gravity model. The World Economy, 39(9), 1478-1505.

4. Santos Silva, J. M., & Tenreyro, S. (2015). Trading partners and trading volumes: implementing the Helpman-Melitz-Rubinstein model empirically. Journal of International Economics, 96(S1), S100-S112.