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Diakses pada 5 Oktober 2020Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/copd/expert-answers/barrel-chest/faq-20058419
Diakses pada 5 Oktober 2020Verywell Health. https://www.verywellhealth.com/barrel-chest-914891
Diakses pada 5 Oktober 2020