diff --git a/3_dimension_reduction/Makefile b/3_dimension_reduction/Makefile
index de8fcb5ddbf7a74c0efced296afaf1c9badaf34d..1bdb44f6fd53f91cd4b19643ca20a7ee97f1c06b 100644
--- a/3_dimension_reduction/Makefile
+++ b/3_dimension_reduction/Makefile
@@ -1,4 +1,4 @@
-all: dimention_reduction.pdf
+all: dimension_reduction.pdf
 
-dimention_reduction.pdf: dimention_reduction.Rmd
-	Rscript -e "rmarkdown::render('dimention_reduction.Rmd')"
+dimension_reduction.pdf: dimension_reduction.Rmd
+	Rscript -e "rmarkdown::render('dimension_reduction.Rmd')"
diff --git a/5_pseudo_time/img/scvelo.png b/5_pseudo_time/img/scvelo.png
new file mode 100644
index 0000000000000000000000000000000000000000..bcd2e93192c2d62a5dab6d420d637b971d76a775
Binary files /dev/null and b/5_pseudo_time/img/scvelo.png differ
diff --git a/5_pseudo_time/pseudo_time.Rmd b/5_pseudo_time/pseudo_time.Rmd
index 36b215b1ab9db226c93340e399d20fc25dd42cf0..ffd81d93b390cb35bcd0381201c1415483addc34 100644
--- a/5_pseudo_time/pseudo_time.Rmd
+++ b/5_pseudo_time/pseudo_time.Rmd
@@ -415,6 +415,16 @@ We can find the optime coupling between time $t_i$ and $t_{i+1}$ accounting for
 
 259,155 cells collected at 39 time points across 18 days
 
+# Velocity
+
+## Velocity
+
+\begin{center}
+  \href{https://scvelo.readthedocs.io/}{
+    \includegraphics[width=0.7\textwidth]{img/scvelo.png}
+  }
+\end{center}
+
 ## Velocity