These are the documents I got from my US sponsor,
1). I-134 Affidavit of Support (Scanned copy)
2). W2 Tax Form (Scanned Copy) - http://www.irs.gov/uac/Form-W-2,-Wage-and-Tax-Statement
3) . Form 1040
1). I-134 Affidavit of Support (Scanned copy)
2). W2 Tax Form (Scanned Copy) - http://www.irs.gov/uac/Form-W-2,-Wage-and-Tax-Statement
3) . Form 1040