Não informado. Extension Folder. North Carolina State College of Agriculture and Engineering, Agricultural Extension Service.
Citação do estilo Chicago (17ª ed.)Não informado. Extension Folder. Raleigh, NC: North Carolina State College of Agriculture and Engineering, Agricultural Extension Service.
Citação MLA (8ª ed.)Não informado. Extension Folder. North Carolina State College of Agriculture and Engineering, Agricultural Extension Service.
Atenció: Aquestes cites poden no estar 100% correctes.