If you are unable to obtain copies of your tax returns, you can request a tax transcript from the Internal Revenue Service which will satisfy the document requirement.
You can order a copy of your tax transcript by clicking on the following link. Please follow the instructions provided: https://sa2.www4.irs.gov/irfof-tra/start.do
You can also order a copy of your tax transcript by calling the Internal Revenue Service at 1-800-908-9946.