title: csproj Reference without HintPath and without ReferencePath Assembly location
body: <p>Usually a csproj file references have either a HintPath or a ReferencePath.</p>
  
  <p>I am doing maintenance on a solution that i did not create. 
  in one of the project files, a reference is not resolving.
  The Reference element opens and closes on itself. and both HintPath is missing and ReferencePath is missing.</p>
  
  <pre><code>&lt;Reference Include="SomeCustomeNameSpace.EnvironmentSettings.Client, Version=4.0.0.0, Culture=neutral, PublicKeyToken=16a2c5caeea1b130d, processorArchitecture=MSIL" /&gt;
  </code></pre>
  
  <p>is there a default location where this assembly might be found? or is it even valid to have a reference like this?</p>