Add Bomze_Overton_2015 and Xu_Xia_Wang_2021

optim.bib

@@ -325,6 +325,17 @@ @article{Boggs_Tolle_1995
     _updated     = {2021-11-24},
 }
 
+@article{Bomze_Overton_2015,
+    author       = {Bomze, I. M. and Overton, M. L.},
+    title        = {Narrowing the difficulty gap for the {Celis–Dennis–Tapia} problem},
+    journaltitle = j-mp,
+    volume       = {151},
+    pages        = {459--476},
+    year         = {2015},
+    _created     = {2022-07-22},
+    _updated     = {2022-07-22},
+}
+
 @inproceedings{Booker_Etal_1998a,
     author    = {Booker, A. J. and {Dennis, Jr.}, J. E. and Frank, P. D. and Moore, D. W. and Serafini, D. B.},
     title     = {Managing surrogate objectives to optimize a helicopter rotor design -- further experiments},
@@ -2902,6 +2913,17 @@ @article{Virtanen_Etal_2020
     _updated     = {2022-04-28},
 }
 
+@article{Xu_Xia_Wang_2021,
+    author       = {Xu, Z. and Xia, Y. and Wang, J.},
+    title        = {Cheaper relaxation and better approximation for multi-ball constrained quadratic optimization and extension},
+    journaltitle = j-jgo,
+    volume       = {80},
+    pages        = {341--356},
+    year         = {2021},
+    _created     = {2022-07-22},
+    _updated     = {2022-07-22},
+}
+
 @article{Wang_Yuan_2014,
     author       = {Wang, X. and Yuan, Y.},
     title        = {An augmented {Lagrangian} trust region method for equality constrained optimization},