diff --git a/OpenMcdf.Ole/OlePropertiesContainer.cs b/OpenMcdf.Ole/OlePropertiesContainer.cs
index 72cbfe0..2e935c5 100644
--- a/OpenMcdf.Ole/OlePropertiesContainer.cs
+++ b/OpenMcdf.Ole/OlePropertiesContainer.cs
@@ -71,7 +71,7 @@ public OlePropertiesContainer(CfbStream cfStream)
         for (int i = 0; i < pStream.PropertySet0.Properties.Count; i++)
         {
             PropertyIdentifierAndOffset propertyIdentifierAndOffset = pStream.PropertySet0.PropertyIdentifierAndOffsets[i];
-            if (propertyIdentifierAndOffset.PropertyIdentifier == 0) continue;
+            if (propertyIdentifierAndOffset.PropertyIdentifier == SpecialPropertyIdentifiers.Dictionary) continue;
             //if (propertyIdentifierAndOffset.PropertyIdentifier == 1) continue;
             //if (propertyIdentifierAndOffset.PropertyIdentifier == 0x80000000) continue;
 
@@ -95,7 +95,7 @@ public OlePropertiesContainer(CfbStream cfStream)
             for (int i = 0; i < propertySet1.Properties.Count; i++)
             {
                 PropertyIdentifierAndOffset propertyIdentifierAndOffset = propertySet1.PropertyIdentifierAndOffsets[i];
-                if (propertyIdentifierAndOffset.PropertyIdentifier is 0 or 0x80000000)
+                if (propertyIdentifierAndOffset.PropertyIdentifier is SpecialPropertyIdentifiers.Dictionary or SpecialPropertyIdentifiers.Locale)
                     continue;
 
                 var p = (ITypedPropertyValue)propertySet1.Properties[i];
diff --git a/OpenMcdf.Ole/PropertySet.cs b/OpenMcdf.Ole/PropertySet.cs
index 196cf0d..2d666b3 100644
--- a/OpenMcdf.Ole/PropertySet.cs
+++ b/OpenMcdf.Ole/PropertySet.cs
@@ -13,7 +13,7 @@ internal sealed class PropertySet
     public void LoadContext(int propertySetOffset, BinaryReader br)
     {
         long currPos = br.BaseStream.Position;
-        int codePageOffset = (int)(propertySetOffset + PropertyIdentifierAndOffsets.First(pio => pio.PropertyIdentifier == 1).Offset);
+        int codePageOffset = (int)(propertySetOffset + PropertyIdentifierAndOffsets.First(pio => pio.PropertyIdentifier == SpecialPropertyIdentifiers.CodePage).Offset);
         br.BaseStream.Seek(codePageOffset, SeekOrigin.Begin);
 
         var vType = (VTPropertyType)br.ReadUInt16();
@@ -30,6 +30,6 @@ public void Add(IDictionary<uint, string> propertyNames)
             Value = propertyNames
         };
         Properties.Add(dictionaryProperty);
-        PropertyIdentifierAndOffsets.Add(new PropertyIdentifierAndOffset() { PropertyIdentifier = 0, Offset = 0 });
+        PropertyIdentifierAndOffsets.Add(new PropertyIdentifierAndOffset() { PropertyIdentifier = SpecialPropertyIdentifiers.Dictionary, Offset = 0 });
     }
 }
diff --git a/OpenMcdf.Ole/PropertySetStream.cs b/OpenMcdf.Ole/PropertySetStream.cs
index b76f30a..0264307 100644
--- a/OpenMcdf.Ole/PropertySetStream.cs
+++ b/OpenMcdf.Ole/PropertySetStream.cs
@@ -214,7 +214,7 @@ public void Write(BinaryWriter bw)
 
     private static IProperty ReadProperty(uint propertyIdentifier, int codePage, BinaryReader br, PropertyFactory factory)
     {
-        if (propertyIdentifier == 0)
+        if (propertyIdentifier == SpecialPropertyIdentifiers.Dictionary)
         {
             DictionaryProperty dictionaryProperty = new(codePage);
             dictionaryProperty.Read(br);
diff --git a/OpenMcdf.Ole/SpecialPropertyIdentifiers.cs b/OpenMcdf.Ole/SpecialPropertyIdentifiers.cs
new file mode 100644
index 0000000..654c852
--- /dev/null
+++ b/OpenMcdf.Ole/SpecialPropertyIdentifiers.cs
@@ -0,0 +1,9 @@
+namespace OpenMcdf.Ole;
+
+// Identifiers for properties that we treat specially.
+internal static class SpecialPropertyIdentifiers
+{
+    public const uint Dictionary = 0;
+    public const uint CodePage = 1;
+    public const uint Locale = 0x80000000;
+}