We talk with the GS1 on how to get your UPC's squared away with amazon. This is in increasingly timely issue as Amaozn has changed its approach to enforce this.

Here's a few helpful links.

https://www.gs1us.org/- homepage
https://www.gs1us.org/tools/gs1-company-database-gepir - look up who licenses which GTIN
https://www.gs1us.org/tools/barcode-estimator/home - barcode estimator
https://next-level-supply-chain-with-gs1us.podcastpage.io/ - GS1 Podcast