PUB-39 requires DOIs for DMTN-006 and DMTN-021. For now, these DOIs are prepared manually since we haven't engineering a technote release process yet.
DOI for DMTN-006 is http://dx.doi.org/10.5281/zenodo.192828 (also needed to configure LSST the Docs deployment).
DOI for DMTN-021 is http://dx.doi.org/10.5281/zenodo.192833 (this also required significant effort to fix reStructuredText issues in the original document before releasing the artifact to Zenodo).
Procedure is roughly: