Unknown. (2023). Pennsylvania department of forestry. Forest Research Institute.
Citazione stile Chigago Style (17a edizione)Unknown. Pennsylvania Department of Forestry. Forest Research Institute, 2023.
Citatione MLA (9a ed.)Unknown. Pennsylvania Department of Forestry. Forest Research Institute, 2023.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.