Procesos de Mercado has free electronic access to all its publications (https://www.procesosdemercado.com/index.php/inicio and https://www.jesushuertadesoto.com/inicio/), which are also available for sale physically (https://www.unioneditorial.net/). All published articles are available in PDF format and have an associated DOI. Any reproduction of the journal's publications will incorporate a complete reference.
DOI (Digital Object Identifier) is the most widely used indicator to identify electronic scientific articles. It guarantees to go directly to the object it identifies and serves as a secure and unique link between users and information providers. In a nutshell, the DOI is the barcode of intellectual property. http://www.doi.org.