diff --git a/src/models/append_graph.rs b/src/models/append_graph.rs
index 9cbdbca..c767566 100644
--- a/src/models/append_graph.rs
+++ b/src/models/append_graph.rs
@@ -7,7 +7,10 @@ pub struct Vertex(usize);
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct Edge(usize);
 
+/// An [`EntityMap`] for [`AppendGraph`] vertices.
 pub type AppendGraphVertexMap<T> = EntityMap<Vertex, T>;
+
+/// An [`EntityMap`] for [`AppendGraph`] edges.
 pub type AppendGraphEdgeMap<T> = EntityMap<Edge, T>;
 
 impl Edge {
diff --git a/src/models/graph.rs b/src/models/graph.rs
index 89ad70e..21bd4d9 100644
--- a/src/models/graph.rs
+++ b/src/models/graph.rs
@@ -6,7 +6,10 @@ use crate::traits::{GraphTopology, GraphTopologyDeletion, IncidenceCursor};
 pub type Vertex = Index<VertexIncidenceHeader, usize, usize>;
 pub type Edge = Index<IncidenceEntry, usize, usize>;
 
+/// An [`EntityMap`] for [`Graph`] vertices.
 pub type GraphVertexMap<T> = EntityMap<Vertex, T>;
+
+/// An [`EntityMap`] for [`Graph`] edges.
 pub type GraphEdgeMap<T> = EntityMap<Edge, T>;
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]