diff --git a/docs/deltaf.md b/docs/deltaf.md
index 8958c0855df42f5db800db7d8a01348f38ea57db..375226675bc52746b1252be65c7c78f2a0e59344 100644
--- a/docs/deltaf.md
+++ b/docs/deltaf.md
@@ -36,7 +36,7 @@ component definitions):
 
 Of course, if data are only available in hdZ (where d=(D-D0)) coordinates, as
 is common with USGS preliminary data, they should be converted into a Cartesian
-system used in (2). See [XYZ Algorithm](XYZ.md) for a discussion on the 
+system used in (2). See the [XYZ Algorithm](XYZ.md) for a discussion on the 
 cartesian coordinate system used.
 
 ## Practical Considerations