Personen
United States. Agricultural Stabilization and Conservation Service
18
United States. Geological Survey
8
United States. Forest Service. Northern Region
6
Arens, S.M.
4
Maugnard, Alexandre
4
Uhrmacher, Martin
4
Wiersma, J.
4
Arak Photo Studio
2
Assendorp, Dan
2
Boyan, John
2
Calame, Wim
2
Dutchess Community College
2
Reichert, Henry
2
Schaminée, Joop H.J.
2
Sýkora, Karlè V.
2
United States. Army
2
Wells, Edward
2
van der Hagen, Harrie G.J.M.
2
van der Meulen, Frank
2