Fix grammar.

diff --git a/examples/step-58/doc/intro.dox b/examples/step-58/doc/intro.dox
index 3a50d99b354da0bbd8f24dc1a4ede26bbf6d6784..f4a9dab9b3554bdbc0c0eb63ecaacfaa5d7a3879 100644 (file)
--- a/examples/step-58/doc/intro.dox
+++ b/examples/step-58/doc/intro.dox
@@ -5,7 +5,7 @@ University) and Yong-Yong Cai (<a href="http://www.csrc.ac.cn/en/">Beijing
 Computational Science Research Center</a>, CSRC) and is the result of the
 first author's time as a visitor at CSRC.
 
-This material is based upon work partially supported National Science
+This material is based upon work partially supported by National Science
 Foundation grants OCI-1148116, OAC-1835673, DMS-1821210, and EAR-1925595;
 and by the Computational Infrastructure in
 Geodynamics initiative (CIG), through the National Science Foundation under