diff --git a/src/ontology/iri_mapped.rs b/src/ontology/iri_mapped.rs
index c681cc8..6e5998e 100644
--- a/src/ontology/iri_mapped.rs
+++ b/src/ontology/iri_mapped.rs
@@ -25,6 +25,31 @@ use super::set::SetIndex;
 
 use std::collections::HashSet;
 
+/// Implements an ontology index that stores for each IRI a set of annotated components in which this IRI occurs.
+/// 
+/// # Examples
+/// 
+/// The following snippet shows the effect of adding an axiom involving two IRIs to a new index.
+/// ```
+/// # use horned_owl::ontology::iri_mapped::IRIMappedIndex;
+/// # use horned_owl::{model::*, ontology::indexed::OntologyIndex};
+/// # fn test_index_example() {
+///   let build = Build::new();
+///   let mut idx = IRIMappedIndex::<RcStr, RcAnnotatedComponent>::new();
+///   let cmp = AnnotatedComponent {
+///       component: Component::DisjointClasses(DisjointClasses(vec![
+///           ClassExpression::Class(build.class("http://www.example.com/#A")),
+///           ClassExpression::Class(build.class("http://www.example.com/#B")),
+///       ])),
+///       ann: Default::default(),
+///   };
+///
+///   idx.index_insert(RcAnnotatedComponent::new(cmp));
+/// 
+///   assert!(idx.component_for_iri(&build.iri("http://www.example.com/#A")).next().is_some());
+///   assert!(idx.component_for_iri(&build.iri("http://www.example.com/#B")).next().is_some());
+/// # }
+/// ```
 #[derive(Debug, Eq, PartialEq)]
 pub struct IRIMappedIndex<A, AA> {
     irindex: RefCell<BTreeMap<IRI<A>, BTreeSet<AA>>>,
@@ -38,7 +63,8 @@ impl<A: ForIRI, AA: ForIndex<A>> IRIMappedIndex<A, AA> {
         }
     }
 
-    fn aa_to_iris(&self, cmp: &AnnotatedComponent<A>) -> HashSet<IRI<A>> {
+    /// Helper that visits an annotated component and extract all the occurring IRIs.
+    fn iris_from_component(cmp: &AnnotatedComponent<A>) -> HashSet<IRI<A>> {
         let mut w = Walk::new(IRIExtract::default());
         w.annotated_component(cmp);
 
@@ -187,7 +213,7 @@ impl<'a, A: ForIRI, AA: ForIndex<A>> IntoIterator for &'a IRIMappedIndex<A,AA> {
 
 impl<A: ForIRI, AA: ForIndex<A>> OntologyIndex<A, AA> for IRIMappedIndex<A, AA> {
     fn index_insert(&mut self, cmp: AA) -> bool {
-        let iris = self.aa_to_iris(cmp.borrow());
+        let iris = Self::iris_from_component(cmp.borrow());
         if !iris.is_empty() {
             for iri in iris.iter() {
                 self.mut_set_for_iri(iri).insert(cmp.clone());
@@ -199,7 +225,7 @@ impl<A: ForIRI, AA: ForIndex<A>> OntologyIndex<A, AA> for IRIMappedIndex<A, AA>
     }
 
     fn index_take(&mut self, cmp: &AnnotatedComponent<A>) -> Option<AnnotatedComponent<A>> {
-        self.aa_to_iris(cmp).iter().fold(None, |val, iri| {
+        Self::iris_from_component(cmp).iter().fold(None, |val, iri| {
             self.mut_set_for_iri(iri)
                 .take(cmp)
                 .map_or(val, |c| Some(c.unwrap()))
@@ -207,7 +233,7 @@ impl<A: ForIRI, AA: ForIndex<A>> OntologyIndex<A, AA> for IRIMappedIndex<A, AA>
     }
 
     fn index_remove(&mut self, cmp: &AnnotatedComponent<A>) -> bool {
-        self.aa_to_iris(cmp).iter().fold(false, |val, iri| {
+        Self::iris_from_component(cmp).iter().fold(false, |val, iri| {
             self.mut_set_for_iri(iri).remove(cmp) || val
         })
     }