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: The majority of these aneurysms were smaller than those of the control group ( 8 + / - 6 . 08 mm versus 11 + / - 5 . 4 mm ; P = 0 . 05 ) .
### Output Text:
The majority of these aneurysms were smaller than those of the control group ( 8 + / - 6 . 08 mm versus 11 + / - 5 . 4 mm ; P = 0 . 05 ) . 