In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: CONCLUSION : This is the first study in the literature investigating a link between angiogenesis soluble markers and ribavirin induced anemia in patients with hepatitis C and we could not find any relation .
### Output Text:
CONCLUSION : This is the first study in the literature investigating a link between angiogenesis soluble markers and <span class="chemical">ribavirin</span> induced anemia in patients with hepatitis C and we could not find any relation . 