diff --git a/bib/sivanov.bib b/bib/sivanov.bib
index d71185c..dfe7103 100644
--- a/bib/sivanov.bib
+++ b/bib/sivanov.bib
@@ -81,7 +81,7 @@
   year      = {2021},
   url       = {https://doi.org/10.1007/s11047-021-09861-3},
   doi       = {10.1007/s11047-021-09861-3},
-  timestamp = {Mon, 22 Nov 2021 00:00:00 +0100},
+  timestamp = {Sat, 09 Apr 2022 01:00:00 +0200},
   biburl    = {https://dblp.org/rec/journals/nc/IvanovV21.bib},
   bibsource = {dblp computer science bibliography, https://dblp.org}
 }
@@ -380,7 +380,7 @@
   year      = {2018},
   url       = {https://doi.org/10.1007/978-3-030-00265-7\_1},
   doi       = {10.1007/978-3-030-00265-7\_1},
-  timestamp = {Sun, 25 Oct 2020 01:00:00 +0200},
+  timestamp = {Sat, 09 Apr 2022 01:00:00 +0200},
   biburl    = {https://dblp.org/rec/conf/birthday/AlhazovF0OV18.bib},
   bibsource = {dblp computer science bibliography, https://dblp.org}
 }
@@ -472,7 +472,7 @@
   year      = {2018},
   url       = {https://doi.org/10.1007/978-3-319-92435-9\_1},
   doi       = {10.1007/978-3-319-92435-9\_1},
-  timestamp = {Sun, 25 Oct 2020 01:00:00 +0200},
+  timestamp = {Sat, 09 Apr 2022 12:39:24 +0200},
   biburl    = {https://dblp.org/rec/conf/uc/AlhazovF018.bib},
   bibsource = {dblp computer science bibliography, https://dblp.org}
 }
@@ -1008,7 +1008,7 @@
   year      = {2013},
   url       = {https://doi.org/10.1007/978-3-642-54239-8\_16},
   doi       = {10.1007/978-3-642-54239-8\_16},
-  timestamp = {Sun, 25 Oct 2020 23:18:19 +0100},
+  timestamp = {Sat, 09 Apr 2022 01:00:00 +0200},
   biburl    = {https://dblp.org/rec/conf/membrane/IvanovV13.bib},
   bibsource = {dblp computer science bibliography, https://dblp.org}
 }
@@ -1033,7 +1033,7 @@
   year      = {2013},
   url       = {https://doi.org/10.1007/978-3-642-39074-6\_8},
   doi       = {10.1007/978-3-642-39074-6\_8},
-  timestamp = {Tue, 14 May 2019 10:00:35 +0200},
+  timestamp = {Sat, 09 Apr 2022 12:39:24 +0200},
   biburl    = {https://dblp.org/rec/conf/uc/FernauFISS13.bib},
   bibsource = {dblp computer science bibliography, https://dblp.org}
 }