Yeah, I second this. Reference letter is mandatory, pay stubs are nice to have. Below is the text from help (?)
Document: Employment Records
You must provide proof of work experience for your current job and for each past position you listed. Proof must include a reference letter from your employer and pay stubs, if you have them.
The reference letter must:
1. be an official document printed on company letterhead
2. include your name, the company’s contact information (address, telephone number and e-mail address), the signature of your immediate
3. show all positions held while employed at the company
4. include these details: job title, duties/responsibilities, job status (if current job), the dates you worked for the company, the number of work hours per week and your annual salary plus benefits.
You must scan all documents for this period of employment and save them as one file. (You must create a separate file for each period of employment.)