WordNet (r) 3.0 (2006):

documented
    adj 1: furnished with or supported by documents; "the first
           documented case of shark attack in those waters" [ant:
           undocumented]
    2: established as genuine [syn: attested, authenticated,
       documented]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "documented":
   absolute, adducible, admissible, attestative, attestive, authentic,
   based on, booked, certain, circumstantial, conclusive, convincing,
   cumulative, damning, decisive, determinative, documentary, down,
   enrolled, entered, evidential, evidentiary, ex parte, eye-witness,
   factual, filed, final, firsthand, founded on, grounded on, hearsay,
   implicit, incontrovertible, indexed, indicative, indisputable,
   inscribed, irrefutable, irresistible, legal, logged, material,
   minuted, nuncupative, of record, official, on file, on record,
   on the books, overwhelming, posted, presumptive, probative,
   recorded, registered, reliable, significant, suggestive, sure,
   symptomatic, telling, valid, weighty, written down