Questione giuridica chiave
Whether the refusal to produce all preparatory documents violated the appellants' right to be heard.
Decisione estratta
No violation was shown; the cantonal court could refuse further evidence after an anticipatory assessment of relevance.
Motivazione estratta
The Federal Court found no arbitrariness in the cantonal court's view that the requested preparatory works were unnecessary because the case did not turn on a historical interpretation requiring all documents.