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: EEG recordings were made in SJL , A / J and C57BL / 6J mice revealing a close correspondence between electrical activity and behavior .
### Output Text:
EEG recordings were made in SJL , A / J and C57BL / 6J mice revealing a close correspondence between electrical activity and behavior . 