Two articles in the latest issue of the IASSIST Quarterly (Vol 42 No 2 (2018)) discuss DDI. "Flexible DDI Storage," the winner of the IASSIST 2017 conference paper competition, describes "a way to model the binding of DDI to applications in a way that it works independent of most version changes and interpretative differences in a standard like DDI without continuous reimplementation." The other article, "Elaborating a Crosswalk Between Data Documentation Initiative (DDI) and Encoded Archival Description (EAD) for an Emerging Data Archive Service Provider," describes a DDI-to-EAD crosswalk at the State Archives of Belgium.
More details: https://www.iassistquarterly.com/index.php/iassist/issue/view/3