diff --git a/mathematics/ATSN.url b/mathematics/ATSN.url
new file mode 100644
index 0000000..46d467a
--- /dev/null
+++ b/mathematics/ATSN.url
@@ -0,0 +1 @@
+https://www.math.upenn.edu/~ghrist/preprints/ATSN.pdf
\ No newline at end of file