add section

paper/references.bib

@@ -8,7 +8,7 @@
   year = {2004},
   doi = {10.26421/QIC4.5-4}
 }
-
+ 
 @article{peres,
   author = {Peres, Asher},
   title = {Separability Criterion for Density Matrices},
@@ -19,7 +19,7 @@
   year = {1996},
   doi = {10.1103/PhysRevLett.77.1413}
 }
-
+ 
 @article{horodeckiPPT,
   author = {Horodecki, Micha{\l} and Horodecki, Pawe{\l} and Horodecki, Ryszard},
   title = {Separability of mixed states: necessary and sufficient conditions},
@@ -30,7 +30,7 @@
   year = {1996},
   doi = {10.1016/S0375-9601(96)00706-2}
 }
-
+ 
 @article{bennettUPB,
   author = {Bennett, Charles H. and DiVincenzo, David P. and Mor, Tal and Shor, Peter W. and Smolin, John A. and Terhal, Barbara M.},
   title = {Unextendible Product Bases and Bound Entanglement},
@@ -41,7 +41,6 @@
   year = {1999},
   doi = {10.1103/PhysRevLett.82.5385}
 }
-}
 
 @article{chenwu,
   author = {Chen, Kai and Wu, Ling-An},
@@ -295,3 +294,47 @@
   year = {2026},
   doi = {10.1103/PhysRevA.113.032440}
 }
+
+
+@book{kato1995perturbation,
+  author    = {Kato, Tosio},
+  title     = {Perturbation Theory for Linear Operators},
+  publisher = {Springer-Verlag},
+  series    = {Classics in Mathematics},
+  year      = {1995},
+  note      = {Reprint of the 1980 second edition}
+}
+
+
+@article{lewissendov2005,
+  author  = {Lewis, A. S. and Sendov, H. S.},
+  title   = {Nonsmooth analysis of singular values. {P}art {I}: Theory},
+  journal = {Set-Valued Analysis},
+  volume  = {13},
+  number  = {3},
+  pages   = {213--241},
+  year    = {2005},
+  doi     = {10.1007/s11228-004-7197-7}
+}
+ 
+@article{zanardirasetti1997,
+  author  = {Zanardi, Paolo and Rasetti, Mario},
+  title   = {Noiseless Quantum Codes},
+  journal = {Physical Review Letters},
+  volume  = {79},
+  number  = {17},
+  pages   = {3306--3309},
+  year    = {1997},
+  doi     = {10.1103/PhysRevLett.79.3306}
+}
+ 
+@article{kribslaflammepoulin2005,
+  author  = {Kribs, David and Laflamme, Raymond and Poulin, David},
+  title   = {Unified and Generalized Approach to Quantum Error Correction},
+  journal = {Physical Review Letters},
+  volume  = {94},
+  number  = {18},
+  pages   = {180501},
+  year    = {2005},
+  doi     = {10.1103/PhysRevLett.94.180501}
+}