diff --git a/references.bib b/references.bib
index 64123bc..cf55652 100644
--- a/references.bib
+++ b/references.bib
@@ -688,7 +688,7 @@
 	title = {No Encore for {Encore}? Ethical Questions for Web-Based Censorship Measurement},
 	journal = {Technology Science},
 	year = {2015},
-	url = {https://techscience.org/a/2015121501/download.pdf},
+	url = {https://censorbib.nymity.ch/pdf/Narayanan2015a.pdf},
 }
 
 @inproceedings{Gosain2017a,
@@ -1054,7 +1054,7 @@
 	publisher = {De Gruyter Open},
 	year = {2016},
 	pages = {83--101},
-	url = {https://www.degruyter.com/downloadpdf/j/popets.2016.2016.issue-4/popets-2016-0030/popets-2016-0030.xml},
+	url = {https://discovery.ucl.ac.uk/id/eprint/1503846/1/popets2016gametheoretic.pdf},
 }
 
 @article{Khattak2016a,
@@ -1066,7 +1066,7 @@
 	publisher = {De Gruyter Open},
 	year = {2016},
 	pages = {37--61},
-	url = {https://www.degruyter.com/downloadpdf/j/popets.2016.2016.issue-4/popets-2016-0028/popets-2016-0028.xml},
+	url = {https://murdoch.is/papers/popets16makingsense.pdf},
 }
 
 @article{Douglas2016a,
@@ -1078,7 +1078,7 @@
 	publisher = {De Gruyter Open},
 	year = {2016},
 	pages = {4--20},
-	url = {https://www.degruyter.com/downloadpdf/j/popets.2016.2016.issue-4/popets-2016-0026/popets-2016-0026.xml},
+	url = {https://censorbib.nymity.ch/pdf/Douglas2016a.pdf},
 }
 
 @inproceedings{Scott2016a,
@@ -1105,7 +1105,7 @@
 	booktitle = {Information Security Conference},
 	publisher = {Springer},
 	year = {2016},
-	url = {https://dke.maastrichtuniversity.nl/zarras/files/Camouflage.pdf},
+	url = {https://censorbib.nymity.ch/pdf/Zarras2016a.pdf},
 }
 
 @inproceedings{Hahn2016a,
@@ -1134,8 +1134,8 @@
 	number = {2},
 	publisher = {De Gruyter Open},
 	year = {2016},
-	pages = {175--192},
-	url = {https://www.degruyter.com/downloadpdf/j/popets.2015.2016.issue-2/popets-2016-0011/popets-2016-0011.xml},
+	pages = {1--18},
+	url = {https://www-users.cse.umn.edu/~hoppernj/mailet_popets.pdf},
 }
 
 @article{McPherson2016a,
@@ -1146,8 +1146,8 @@
 	number = {3},
 	publisher = {De Gruyter Open},
 	year = {2016},
-	pages = {212--225},
-	url = {https://www.degruyter.com/downloadpdf/j/popets.2016.2016.issue-3/popets-2016-0024/popets-2016-0024.xml},
+	pages = {1--14},
+	url = {https://www.cs.cornell.edu/~shmat/covertcast/covertcast.pdf},
 }
 
 @inproceedings{Kohls2016a,
@@ -1156,7 +1156,7 @@
 	booktitle = {ASIA Computer and Communications Security},
 	publisher = {ACM},
 	year = {2016},
-	url = {https://hgi.rub.de/media/emma/veroeffentlichungen/2016/03/17/SkypeLine-AsiaCCS16.pdf},
+	url = {https://poepper.net/papers/SkypeLine-AsiaCCS16.pdf},
 }
 
 @article{Al-Saqaf2016a,
@@ -1796,7 +1796,7 @@
 	title = {{Message In A Bottle}: Sailing Past Censorship},
 	publisher = {ACM},
 	year = {2013},
-	url = {https://seclab.cs.ucsb.edu/media/uploads/papers/invernizzi_miab_acsac_2013.pdf},
+	url = {https://sites.cs.ucsb.edu/~chris/research/doc/acsac13_message.pdf},
 }
 
 @inproceedings{Jones2014a,
@@ -2124,7 +2124,7 @@
 	booktitle = {Security Protocols},
 	publisher = {Springer},
 	year = {2014},
-	url = {https://security.cs.georgetown.edu/~msherr/papers/censorship-as-sideeffect.pdf},
+	url = {https://censorbib.nymity.ch/pdf/Tan2014a.pdf},
 }
 
 @inproceedings{Thomas2012a,
@@ -2178,7 +2178,7 @@
 	booktitle = {Cryptology and Network Security},
 	publisher = {Springer},
 	year = {2014},
-	url = {https://gnunet.org/sites/default/files/paper_cans2014_camera_ready.pdf},
+	url = {https://git.gnunet.org/bibliography.git/plain/docs/paper_cans2014_camera_ready.pdf},
 }
 
 @inproceedings{Waldman2000a,
@@ -2187,7 +2187,7 @@
 	booktitle = {USENIX Security Symposium},
 	publisher = {USENIX},
 	year = {2000},
-	url = {https://www.eecs.harvard.edu/~mema/courses/cs264/papers/waldman00publius.pdf},
+	url = {https://www.usenix.org/legacy/events/sec2000/waldman/waldman.pdf},
 }
 
 @inproceedings{Waldman2001a,