In the context of IMDb film credits, what constitutes definitive proof of involvement in a project when formal documentation is unavailable?

When formal documentation is unavailable, corroborating evidence from multiple, independent, and reputable sources is required to establish definitive proof of involvement in a project. This means gathering verifiable information from several credible sources that independently confirm your participation. Examples of such evidence include: screen captures from the film or TV show where the person is clearly visible and identifiable in a credited role; official press releases from the production company or distributor that specifically name the individual and their role; or verifiable news articles from established entertainment publications or trade journals that mention the person's involvement. Submissions from other credited members of the production, especially key personnel like directors or producers, can provide supporting testimony, but are not definitive on their own. The more independent and verifiable sources that can attest to the person's involvement, the stronger the case for adding the credit to their IMDb profile. Isolated or self-published sources are generally insufficient.