Add Ramzi's OMS paper ref

README.md

@@ -5,6 +5,10 @@
 This code *in this branch* is the code used to make the experiments in paper:
 [Gwenaël Samain, Sébastien Bourguignon, Jordan Ninin. Techniques for accelerating Branch-and-Bound algorithms dedicated to sparse optimization. 2022. {hal-03661177} ](https://hal.science/hal-03661177)
 
+It's based on the contributions published in [Ramzi Ben Mhenni, Sébastien Bourguignon, and Jordan Ninin. Global optimization for sparse
+solution of least squares problems. Optimization Methods and Software, 2021.](https://www.tandfonline.com/doi/full/10.1080/10556788.2021.1977809),
+as well as on the underlying code.
+
 ## How to build
 
 This project has two mandatory dependencies: