diff --git a/examples/curve_fitting.c b/examples/curve_fitting.c
index fb75d7d..47b551e 100644
--- a/examples/curve_fitting.c
+++ b/examples/curve_fitting.c
@@ -147,7 +147,8 @@
   ceres_init(argc, argv);
 
   /* Note: Typically it is better to compact m and c into one block,
-   * but in this case use separate blocks for illustration. */
+   * but in this case use separate blocks to illustrate the use of
+   * multiple parameter blocks. */
   double m = 0.0;
   double c = 0.0;
   double *parameter_pointers[] = { &m, &c };
diff --git a/internal/ceres/graph_algorithms.h b/internal/ceres/graph_algorithms.h
index f38a13f..ca3a2fe 100644
--- a/internal/ceres/graph_algorithms.h
+++ b/internal/ceres/graph_algorithms.h
@@ -43,7 +43,8 @@
 namespace ceres {
 namespace internal {
 
-// Compare two vertices of a graph by their degrees.
+// Compare two vertices of a graph by their degrees, if the degrees
+// are equal then order them by their ids.
 template <typename Vertex>
 class VertexTotalOrdering {
  public: