Update README.md

README.md

@@ -13,6 +13,10 @@ If you are using this code, please cite:
 + patent
 
     Cao Bin, Zhang Tong-yi, Wang Yuanhao, Tian Yuan, Sun Sheng. Bayesian global optimization package for material design [2022SR1481726], 2022, GitHub : github.com/Bin-Cao/Bgolearn.
+
++ paper
+
+    Cao, Bin and Su, Tianhao and Yu, Shuting and Li, Tianyuan and Zhang, Taolue and Dong, Ziqiang and Zhang, Tong-Yi, Active Learning Accelerates the Discovery of High Strength and High Ductility Lead-Free Solder Alloys. Available at SSRN: https://ssrn.com/abstract=4686075 or http://dx.doi.org/10.2139/ssrn.4686075
 
 ## links
 ![Screenshot 2023-11-16 at 11 23 35](https://github.com/Bin-Cao/Bgolearn/assets/86995074/cd0d24e4-06db-45f7-b6d6-12750fa8b819)