No. The best OpenVSP paper is available
here. If you don't have access, you can download a preprint
here.
However, this document does not go into the theory of OpenVSP.
There are other OpenVSP publications listed
here. Some of those cover individual features in-depth (FitModel, DegenGeom, WaveDrag, SubSurfaces, etc).
By and large, I have found that OpenVSP users don't care about the theory of OpenVSP the way they would about a physics-based solver. Just as most CAD users don't care about the theory behind their CAD program. To my knowledge, SolidWorks and CATIA do not publish theory manuals the way FEA and CFD solvers do.
At the most recent Workshop, I did a presentation on the architecture design of OpenVSP. If someone is interested in developing the code, it is a good overview. The
Slides and
Video are both available.
Instead of expending a bunch of effort on writing and maintaining a manual that nobody would ever read, we try to put our limited effort into places that will benefit the most users. New features, bug fixes, video documentation, etc.
If you have specific questions on how a particular feature works, feel free to ask and I am happy to explain it. If there is any more context to your request, let me know that too -- for example, if you're interested in modifying a feature, I might talk more about the software implementation -- whereas if you're interested in duplicating a feature somewhere else, I might talk more about the math behind it all.
However, if you're just looking for a paper to cite, you're best off using the first one I linked to.
Rob