diff --git a/test/pdfs/hmm.pdf.link b/test/pdfs/hmm.pdf.link
new file mode 100644
index 000000000..5ba2534d0
--- /dev/null
+++ b/test/pdfs/hmm.pdf.link
@@ -0,0 +1 @@
+http://speech.tifr.res.in/tutorials/hmmTutExamplesAlgo.pdf