U. S. Dept. of Labor. Office of Occupational Safety and the International Division & U. S. Dept. of Labor Safety Training Programs. (1967). Preventive maintenance for safety. Govt. Print. Off.
Lua i Stíl Chicago (17ú heag.)U. S. Dept. of Labor. Office of Occupational Safety and the International Division agus U. S. Dept. of Labor Safety Training Programs. Preventive Maintenance for Safety. Washington, D. C: Govt. Print. Off, 1967.
Lua MLA (9ú heag.)U. S. Dept. of Labor. Office of Occupational Safety and the International Division agus U. S. Dept. of Labor Safety Training Programs. Preventive Maintenance for Safety. Govt. Print. Off, 1967.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.