I was told that one of the mandatory initial evidence requirements for filing I-130 for my father is my parents' marriage-certificate. Considering that they were married 48 years ago, Municipal officials in that town are refusing to give us a non-availability certificate (NAC). Would a self attested letter be a replacement for the marriage NAC? If so, can I get a sample of this letter from you? I am willing to provide two notarized affidavits and other secondary evidences such as copy of wedding invitation card etc. What are my alternatives to marriage certificate?