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: A correlation of the blood pressure was neither found in the development nor in the attempt to suppress the development of heart hypertrophy with the two beta - receptor blockers .
### Output Text:
A correlation of the blood pressure was neither found in the development nor in the attempt to suppress the development of heart hypertrophy with the two beta - receptor blockers . 