There is a distinction between court proceedings and summary proceedings, especially when it comes to preliminary measures. In court proceedings, the claimant must provide conclusive evidence of their rights. With preliminary measures in summary proceedings, the claimant only needs to show that their rights are plausible. In both cases, a statement from the alleged injured party alone is never sufficient.
Evidence in summary proceedings is usually provided in the form of physical records.
In these proceedings in particular, other forms of evidence are admissible as long as the taking of evidence does not substantially delay the proceedings.