Não informado. (1972). Agricultural engineer. Institution of Agricultural Engineers.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Agricultural Engineer. Bedford, Inglaterra: Institution of Agricultural Engineers, 1972.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Agricultural Engineer. Institution of Agricultural Engineers, 1972.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.