Não informado. (1968). Professional Engineer. National Society of Professional Engineers.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNão informado. Professional Engineer. Jersey City, NJ: National Society of Professional Engineers, 1968.
M.L.A (8 ম সংস্করণ) উদ্ধৃতিNão informado. Professional Engineer. National Society of Professional Engineers, 1968.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.