A great paper by Enisa on honeypots:
An increasing number of complex attacks demand improved early warning detection capabilities for CERTs. By having threat intelligence collected without any impact on production infrastructure, CERTs can better defend their constituencies assets. Honeypots are powerful tools that can be used to achieve this goal. This document is the final report of the ‘Proactive Detection of Security Incidents: Honeypots’ study.
Click HERE to get it.