A survey on the rules governing lobbying in the member states, other community institutions and third countries has been carried out by the Commission in 1990. It is attached to the communication of 1992. It is no longer up to date.
read the survey
Rules on lobbying and intergroups in the national parliaments of the Member States. Working document (1996)
Lobbying in the European Union: current rules and practices. Working document (2003)
Communication: An open and structured dialogue between the Commission and special interest groups