diff --git a/lib/src/io/syntax.rs b/lib/src/io/syntax.rs
index 2c402a4b..4eb3ecb7 100644
--- a/lib/src/io/syntax.rs
+++ b/lib/src/io/syntax.rs
@@ -17,7 +17,10 @@ pub trait FileSyntax: Sized {
 }
 
 /// [RDF graph](https://www.w3.org/TR/rdf11-concepts/#dfn-graph) serialization formats.
+///
+/// This enumeration is non exhaustive. New syntaxes like JSON-LD will be added in the future.
 #[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
+#[non_exhaustive]
 pub enum GraphSyntax {
     /// [N-Triples](https://www.w3.org/TR/n-triples/)
     NTriples,
@@ -119,7 +122,10 @@ impl FileSyntax for GraphSyntax {
 }
 
 /// [RDF dataset](https://www.w3.org/TR/rdf11-concepts/#dfn-rdf-dataset) serialization formats.
+///
+/// This enumeration is non exhaustive. New syntaxes like JSON-LD will be added in the future.
 #[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
+#[non_exhaustive]
 pub enum DatasetSyntax {
     /// [N-Quads](https://www.w3.org/TR/n-quads/)
     NQuads,
diff --git a/lib/src/sparql/model.rs b/lib/src/sparql/model.rs
index 374cdeaf..5a863b62 100644
--- a/lib/src/sparql/model.rs
+++ b/lib/src/sparql/model.rs
@@ -99,7 +99,10 @@ impl From<QuerySolutionsIterator> for QueryResult {
 }
 
 /// [SPARQL query](https://www.w3.org/TR/sparql11-query/) serialization formats
+///
+/// This enumeration is non exhaustive. New syntaxes like CSV will be added in the future.
 #[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
+#[non_exhaustive]
 pub enum QueryResultSyntax {
     /// [SPARQL Query Results XML Format](http://www.w3.org/TR/rdf-sparql-XMLres/)
     Xml,