Certifications Documents / American Welding Society. Specification for the Certification of Welding Sales Representatives.
Citazione stile Chigago Style (17a edizione)Certifications Documents / American Welding Society. Specification for the Certification of Welding Sales Representatives.
Citatione MLA (9a ed.)Certifications Documents / American Welding Society. Specification for the Certification of Welding Sales Representatives.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.