The original EU Regulation 2007/861, which introduced the European Small Claims Procedure is available here.

The EU Regulation 2015/2421, which amended the EU Regulation 2007/861, is available here.

The European Small Claims Procedure is explained here on European e-Justice portal. It is described here on Your Europe website, as well.

Here you can find a brief introduction which European Commission provides about the European Small Claims Procedure.