diff --git a/Octokit.Tests/Clients/ReferencesClientTests.cs b/Octokit.Tests/Clients/ReferencesClientTests.cs
index 20f705ff..bd914aea 100644
--- a/Octokit.Tests/Clients/ReferencesClientTests.cs
+++ b/Octokit.Tests/Clients/ReferencesClientTests.cs
@@ -79,17 +79,17 @@ namespace Octokit.Tests.Clients
             {
                 var client = new ReferencesClient(Substitute.For<IApiConnection>());
 
-                await AssertEx.Throws<ArgumentNullException>(async () => await client.Create(null, "name", new NewReference()));
-                await AssertEx.Throws<ArgumentNullException>(async () => await client.Create("owner", null, new NewReference()));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Create(null, "name", new NewReference("heads/develop", "sha")));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Create("owner", null, new NewReference("heads/develop", "sha")));
                 await AssertEx.Throws<ArgumentNullException>(async () => await client.Create("owner", "name", null));
-                await AssertEx.Throws<ArgumentException>(async () => await client.Create("", "name", new NewReference()));
-                await AssertEx.Throws<ArgumentException>(async () => await client.Create("owner", "", new NewReference()));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Create("", "name", new NewReference("heads/develop", "sha")));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Create("owner", "", new NewReference("heads/develop", "sha")));
             }
 
             [Fact]
             public async Task PostsToCorrectUrl()
             {
-                var newReference = new NewReference();
+                var newReference = new NewReference("heads/develop", "sha");
                 var connection = Substitute.For<IApiConnection>();
                 var client = new ReferencesClient(connection);
 
@@ -98,5 +98,61 @@ namespace Octokit.Tests.Clients
                 connection.Received().Post<Reference>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/repo/git/refs"), newReference);
             }
         }
+
+        public class TheUpdateMethod
+        {
+            [Fact]
+            public async Task EnsuresNonNullArguments()
+            {
+                var client = new ReferencesClient(Substitute.For<IApiConnection>());
+
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Update(null, "name", "heads/develop", new ReferenceUpdate("sha")));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Update("owner", null, "heads/develop", new ReferenceUpdate("sha")));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Update("owner", "name", null, new ReferenceUpdate("sha")));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Update("owner", "name", "heads/develop", null));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Update("", "name", "heads/develop", new ReferenceUpdate("sha")));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Update("owner", "", "heads/develop", new ReferenceUpdate("sha")));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Update("owner", "name", "", new ReferenceUpdate("sha")));
+            }
+
+            [Fact]
+            public async Task PostsToCorrectUrl()
+            {
+                var referenceUpdate = new ReferenceUpdate("sha");
+                var connection = Substitute.For<IApiConnection>();
+                var client = new ReferencesClient(connection);
+
+                await client.Update("owner", "repo", "heads/develop", referenceUpdate);
+
+                connection.Received().Patch<Reference>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/repo/git/refs/heads/develop"), referenceUpdate);
+            }
+        }
+
+        public class TheDeleteMethod
+        {
+            [Fact]
+            public async Task EnsuresNonNullArguments()
+            {
+                var client = new ReferencesClient(Substitute.For<IApiConnection>());
+
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Delete(null, "name", "heads/develop"));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Delete("owner", null, "heads/develop"));
+                await AssertEx.Throws<ArgumentNullException>(async () => await client.Delete("owner", "name", null));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Delete("", "name", "heads/develop"));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Delete("owner", "", "heads/develop"));
+                await AssertEx.Throws<ArgumentException>(async () => await client.Delete("owner", "name", ""));
+            }
+
+            [Fact]
+            public async Task RequestsCorrectUrl()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new ReferencesClient(connection);
+
+                await client.Delete("owner", "repo", "heads/develop");
+
+                connection.Received().Delete(Arg.Is<Uri>(u => u.ToString() == "repos/owner/repo/git/refs/heads/develop"));
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/Octokit/Models/Request/NewReference.cs b/Octokit/Models/Request/NewReference.cs
index 60386a7c..d6c58ab9 100644
--- a/Octokit/Models/Request/NewReference.cs
+++ b/Octokit/Models/Request/NewReference.cs
@@ -2,7 +2,16 @@
 {
     public class NewReference
     {
-        public string Ref { get; set; }
-        public string Sha { get; set; }
+        public NewReference(string @ref, string sha)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(@ref, "ref");
+            Ensure.ArgumentNotNullOrEmptyString(sha, "sha");
+
+            Ref = @ref;
+            Sha = sha;
+        }
+
+        public string Ref { get; private set; }
+        public string Sha { get; private set; }
     }
 }
\ No newline at end of file
diff --git a/Octokit/Models/Request/ReferenceUpdate.cs b/Octokit/Models/Request/ReferenceUpdate.cs
index 0b719cde..b2bf7442 100644
--- a/Octokit/Models/Request/ReferenceUpdate.cs
+++ b/Octokit/Models/Request/ReferenceUpdate.cs
@@ -4,11 +4,13 @@
     {
         public ReferenceUpdate(string sha, bool force = false)
         {
+            Ensure.ArgumentNotNullOrEmptyString(sha, "sha");
+
             Sha = sha;
             Force = force;
         }
 
-        public string Sha { get; set; }
-        public bool Force { get; set; }
+        public string Sha { get; private set; }
+        public bool Force { get; private set; }
     }
 }
\ No newline at end of file