Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:

Convert text to sql: Which authors have submitted to more than one workshop? | workshop : workshop_id , date , venue , name | submission : submission_id , scores , author , college | acceptance : submission_id , workshop_id , result | acceptance.workshop_id = workshop.workshop_id | acceptance.submission_id = submission.submission_id | 

### Response:

select _ from _ group by _ having count ( distinct _ ) > _ | select submission.author from acceptance join submission on acceptance.submission_id = submission.submission_id group by submission.author having count ( distinct acceptance.workshop_id ) > 1