Reading the list of References from csproj files

The XPath should be /Project/ItemGroup/Reference, and you have forgot the namespace. I'd just use XLINQ - dealing with namespaces in XPathNavigator is rather messy. So:

    XNamespace msbuild = "http://schemas.microsoft.com/developer/msbuild/2003";
    XDocument projDefinition = XDocument.Load(fullProjectPath);
    IEnumerable<string> references = projDefinition
        .Element(msbuild + "Project")
        .Elements(msbuild + "ItemGroup")
        .Elements(msbuild + "Reference")
        .Select(refElem => refElem.Value);
    foreach (string reference in references)
    {
        Console.WriteLine(reference);
    }

Building on @Pavel Minaev's answer, this is what worked for me (notice the added .Attributes line to read the Include attribute)

XNamespace msbuild = "http://schemas.microsoft.com/developer/msbuild/2003";
    XDocument projDefinition = XDocument.Load(@"D:\SomeProject.csproj");
    IEnumerable<string> references = projDefinition
        .Element(msbuild + "Project")
        .Elements(msbuild + "ItemGroup")
        .Elements(msbuild + "Reference")
        .Attributes("Include")    // This is where the reference is mentioned       
        .Select(refElem => refElem.Value);
    foreach (string reference in references)
    {
        Console.WriteLine(reference);
    }