I need a sole source document. Where can I find it? March 18, 2021 18:03 Updated You can download a PDF of our sole source letter: Sole source letter (PDF) Related articles I need a copy of your W-9. Where can I find it? How do you determine shipping rates? Can I write to Bella and Rosie? What is the difference between Intervention levels and Reading Recovery levels? Do you charge sales tax?