Internal Revenue Service: How Long to Keep Records http://www.irs.gov/publications/p583/ar02.html#d0e629 IRS: Starting a Business and Keeping Records Publication 583 http://www.irs.gov/publications/p583/ar02.html#d0e629 Publication 583 sample record system cash-basis IRS: Publication 583 Publication 583 Cash basis Recordkeeping IRS: Publication 583 IRS Publication 583 cash-basis W-5 Publication 583 start up costs