TIL - Copy References in GAC to output folder

A while back I had this problem, looks like there is a simple solution:

<Reference Include="DocumentFormat.OpenXml, Version=2.5.5631.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
 <SpecificVersion>False</SpecificVersion>
 <Private>True</Private> <HintPath>..\..\..\OpenXml SDK 2.5\DocumentFormat.OpenXml.dll</HintPath>
</Reference>

Setting <Private>True</Private> ensures that the reference is copied to the output folder, looks like setting it to Copy Local, just doesn't do the trick