Avicii's Death Certificate Reveals Islamic Calendar Reference

Avicii's death certificate has been released -- and while it doesn't reveal much -- there is an interesting reference to the Islamic calendar on the form.

According to the doc -- obtained by TMZ -- Avicii's date of death in the Hijri calendar is April 8, 1439. His religion is listed as Christian of Swedish nationality. His name and date of birth are redacted for some reason, yet the certificate was released to us as his.

TMZ broke the story ... the incredibly talented DJ used a broken glass to cut himself and commit suicide. The gash -- whether it was to his neck or wrist -- caused massive bleeding.