Fix typo in NIST url.
Change-Id: I27937dc4bf6f0216d54be5c90d9f950b8ced87af
diff --git a/docs/source/nnls_tutorial.rst b/docs/source/nnls_tutorial.rst
index acbb9a1..3c39086 100644
--- a/docs/source/nnls_tutorial.rst
+++ b/docs/source/nnls_tutorial.rst
@@ -773,7 +773,7 @@
#. `nist.cc
<https://ceres-solver.googlesource.com/ceres-solver/+/master/examples/nist.cc>`_
implements and attempts to solves the `NIST
- <http://www.itl.nist.gov/div898/strd/nls/nls_main.shtm>`_
+ <http://www.itl.nist.gov/div898/strd/nls/nls_main.shtml>`_
non-linear regression problems.
#. `more_garbow_hillstrom.cc
