Không rõ. (2001). Product Planning and Development. Youth PublishingHouse.
Παραπομπή Chicago StyleKhông rõ. Product Planning and Development. Youth PublishingHouse, 2001.
Παραπομπή MLAKhông rõ. Product Planning and Development. Youth PublishingHouse, 2001.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.