Birte Christensen-Dalsgaard, Director of Development, discusses Summa and other topics in a new podcast (CNI Podcast: An Interview with Birte Christensen-Dalsgaard, Director of Development at the State and University Library, Denmark).
Here's an excerpt from the podcast abstract:
Summa is an open source system implementing modular, service-based architecture. It is based on the fundamental idea "free the content from the proprietary library systems," where the discovery layer is separated from the business layer. In doing so, any Internet technology can be used without the limitations traditionally set by proprietary library systems, and there is the flexibility to integrate or to be integrated into other systems. A first version of a Fedora—Summa integration has been developed.
A white paper is available that examines the system in more detail.