American National Standards Institute. (1989). Standard for Accrediation of Test Facilities for AWS Certified Welder Program - AWS QC 4-89. American: American Welding Society.
Παραπομπή Chicago StyleAmerican National Standards Institute. Standard for Accrediation of Test Facilities for AWS Certified Welder Program - AWS QC 4-89. American: American Welding Society, 1989.
Παραπομπή MLAAmerican National Standards Institute. Standard for Accrediation of Test Facilities for AWS Certified Welder Program - AWS QC 4-89. American: American Welding Society, 1989.
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