| Http://: https://www.hopkinsmedicine.org/health/conditions-and-diseases/asthma/occupational-asthma |
| Http://: https://medlineplus.gov/ency/article/000110.htm |
| Http://: https://www.hopkinsmedicine.org/health/conditions-and-diseases/asthma/occupational-asthma |
| Http://: https://medlineplus.gov/ency/article/000110.htm |