diff --git a/tests/downloadedpapers/.gitignore b/tests/downloadedpapers/.gitignore
index a136337..8cd81cd 100644
--- a/tests/downloadedpapers/.gitignore
+++ b/tests/downloadedpapers/.gitignore
@@ -1 +1,6 @@
+# Ignore stray downloaded PDFs, but track the known test fixtures so CI
+# does not depend on the (flaky) external publisher servers.
 *.pdf
+!bg-8-515-2011.pdf
+!esd-4-11-2013.pdf
+!esd-4-11-2013-supplement.pdf
diff --git a/tests/downloadedpapers/bg-8-515-2011.pdf b/tests/downloadedpapers/bg-8-515-2011.pdf
new file mode 100644
index 0000000..bfbba28
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diff --git a/tests/downloadedpapers/esd-4-11-2013-supplement.pdf b/tests/downloadedpapers/esd-4-11-2013-supplement.pdf
new file mode 100644
index 0000000..5abe918
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diff --git a/tests/downloadedpapers/esd-4-11-2013.pdf b/tests/downloadedpapers/esd-4-11-2013.pdf
new file mode 100644
index 0000000..557136a
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