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: This study shows that 17alpha - ethinylestradiol ( EE ) - induced intrahepatic cholestasis in rats is associated with selective inhibition of the neutral pathway of bile salt ( BS ) synthesis .
### Output Text:
This study shows that <span class="chemical">17alpha - ethinylestradiol</span> ( <span class="chemical">EE</span> ) - induced intrahepatic cholestasis in rats is associated with selective inhibition of the neutral pathway of <span class="chemical">bile salt</span> ( <span class="chemical">BS</span> ) synthesis . 