Does anyone know about antique boxing posters?

i found an original poster that's in awesome shape from Mexico vs. Puerto Rico fight between Ramirez and Camacho. It was on August 10, 1985 at the Rivera in Las Vegas. I also have a June 6, 1985 D-Day Spinks vs. MacDonald fight at the Rivera in Vegas. Both are originals i found going through my grandfathers belongings. Does anyone know where i can get more information on them or if their worth anything? Thanks!!