Open Access Policy

Journal PPD is an open-access journal which means that all content is freely available without charge to the users. All open access papers are licensed and distributed under the terms of the Creative Commons Attribution- Non-Commercial 4.0 International License, which permits authors and readers unrestricted use, distribution, and reproduction of the material in any medium, provided that the original work is properly cited. This is enabled under the terms of Attribution and Non-Commercial usage of the material.