diff --git a/README.md b/README.md
index 31310ec..b4e8544 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ Serde YAML
 [<img alt="build status" src="https://img.shields.io/github/actions/workflow/status/acatton/serde-yaml-ng/ci.yml?branch=master&style=for-the-badge" height="20">](https://github.com/acatton/serde-yaml-ng/actions?query=branch%3Amaster)
 
 Rust library for using the [Serde] serialization framework with data in [YAML]
-file format.
+file format. This library only follows the [YAML specification 1.1.](https://yaml.org/spec/1.1/).
 
 This library is a fork from the latest commit of [serde-yaml](https://github.com/dtolnay/serde-yaml),
 which was `200950`.
diff --git a/src/lib.rs b/src/lib.rs
index a63fe8f..7428a98 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,7 +7,9 @@
 //! <br>
 //!
 //! Rust library for using the [Serde] serialization framework with data in
-//! [YAML] file format. _(This project is no longer maintained.)_
+//! [YAML] file format.
+//!
+//! This version only support the [YAML Specification 1.1](https://yaml.org/spec/1.1/)
 //!
 //! [Serde]: https://github.com/serde-rs/serde
 //! [YAML]: https://yaml.org/
diff --git a/src/value/index.rs b/src/value/index.rs
index 5c11c12..82de731 100644
--- a/src/value/index.rs
+++ b/src/value/index.rs
@@ -29,14 +29,14 @@ impl Index for usize {
     fn index_into<'v>(&self, v: &'v Value) -> Option<&'v Value> {
         match v.untag_ref() {
             Value::Sequence(vec) => vec.get(*self),
-            Value::Mapping(vec) => vec.get(&Value::Number((*self).into())),
+            Value::Mapping(vec) => vec.get(Value::Number((*self).into())),
             _ => None,
         }
     }
     fn index_into_mut<'v>(&self, v: &'v mut Value) -> Option<&'v mut Value> {
         match v.untag_mut() {
             Value::Sequence(vec) => vec.get_mut(*self),
-            Value::Mapping(vec) => vec.get_mut(&Value::Number((*self).into())),
+            Value::Mapping(vec) => vec.get_mut(Value::Number((*self).into())),
             _ => None,
         }
     }
diff --git a/tests/test_value.rs b/tests/test_value.rs
index 16681bc..5a492db 100644
--- a/tests/test_value.rs
+++ b/tests/test_value.rs
@@ -143,7 +143,7 @@ fn test_tagged() {
         Variant(usize),
     }
 
-    let value = serde_yaml_ng::to_value(&Enum::Variant(0)).unwrap();
+    let value = serde_yaml_ng::to_value(Enum::Variant(0)).unwrap();
 
     let deserialized: serde_yaml_ng::Value = serde_yaml_ng::from_value(value.clone()).unwrap();
     assert_eq!(value, deserialized);