interinstitutional agreement on the quality of drafting of community legislation
You can find this agreement (referred to in the Alliance for Natural Health Case) here.
Point 10 states:
10. The purpose of the recitals is to set out concise reasons for the chief provisions of the enacting terms, without reproducing or paraphrasing them. They shall not contain normative provisions or political exhortations.
Point 13 states:
13. Where appropriate, an article shall be included at the beginning of the enacting terms to define the subject matter and scope of the act.