Is it possible to add a reference and not load the associated DLLs

Is it possible to add a reference and not load the associated DLLs

I have a Winforms application that relies on a 3rd party SDK. I've
included the .NET reference in the application, but don't always need/use
it.
Is it possible have a reference but instruct it to only load the DLLs when
required?
(PDFSharp (another reference I use) appears to only load when a PdfSharp
method is called, which makes me wonder if it's something I can control.)