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: METHODS : We used computerized pharmacy records to identify all adult psychiatric inpatients treated with clozapine ( 1995 - 96 ) , reviewed their medical records to score incidence and severity of delirium , and tested associations with potential risk factors .
### Output Text:
METHODS : We used computerized pharmacy records to identify all adult psychiatric inpatients treated with <span class="chemical">clozapine</span> ( 1995 - 96 ) , reviewed their medical records to score incidence and severity of delirium , and tested associations with potential risk factors . 