sop publishes all its journals in full open access under a Creative Commons (CC BY) license. This allows the scientific community and the general public to gain unlimited, free and immediate access to scholarly articles, and to reuse the content freely provided that proper attribution is given to the original authors.

To cover the cost for providing our high-quality publishing service and free access to readers, authors pay a one-time article processing charge (APC) for manuscripts accepted after peer-review. There are no charges for rejected articles, no submission charges, and no surcharges based on the length of an article, figures or supplementary data. Editorial items (Editorials, Corrections, Additions, Retractions, Letters, Comments, etc.) are published free of charge.

APCs cover the following:

1. The editorial procedure, including administration related to peer review, author revisions, and final decision-making. sop employs in-house staff to manage the majority of this process, leaving editorial board members to make key scientific decisions and allowing them to concentrate on their research. To demonstrate its appreciation of the important work done by reviewers and editorial board members, sop provides them with APC discounts and waivers. APCs also cover for the administrative work done for rejected articles.

2. Article production: professional language editing, type-setting, formatting, and production in PDF.

3. Article hosting and dissemination: website maintenance, contact with indexing databases.

4. Journal administration: including managing the journal website and editorial board, and promotion of the journal among the research community.

The APC by journal is given in the table below. Please note that the APCs for articles submitted after 31 December 2019 will change for several journals, see the following page for details.