Introduction

Economic integration processes address fostering cooperation. A particular form of organization in the European Union concerns Euroregions, cross-border areas with more interaction for different reasons (proximity, common cultural and historical aspects, people and economic interactions). However, they face some challenges due to the fact of being affected by different frameworks and regulations in particular in the economic field. They can be understood as frontier or meeting places.

The integration process fosters structures to enable cooperation. Thus, they formalize or institutionalize an informal cooperation. Euroregions and other forms of cooperation (eurocities, eurodistricts, cooperation organizations) have been raised specially since the 1990s, with more than 150 currently active. They show a high level of diversity concerning different socioeconomic issues (size, productive specialization...).

Even though many definitions of Euroregions can be found in the literature, in simple terms they can be identified as European cross-border structures that play influential roles on the borders of European countries. This is especially important in a context characterized by uncertainties that continue to challenge the European Integration process (Durà et al., 2018). However, since Euroregions operate across country borders and vary widely in their particular forms, it is not possible to associate this term with a unique legal framework.

A more precise definition can be found in the definition provided by the Association of European Border Regions that sets the following criteria for the identification of these cross-border structures: first, these can constitute an association of local and regional authorities on either side of the national border, sometimes with a parliamentary assembly; second, they can constitute a transfrontier association with a permanent secretariat and a technical and administrative team with own resources; third, they can be of a private law nature, based on non-profit-making associations or foundations on either side of the border in accordance with the respective national law in force; and fourth, they can be of a public law nature, based on inter-state agreements, dealing among other things, with the participation of territorial authorities (Committee on Regional Development, 2005).

It should be underlined that interregional collaboration in Europe undergoes dynamics and structural changes due to both spontaneous and policy-driven projects between regional governments and enterprises, among others (Sirtori et al., 2019). This is also reflected in the transformations of the governance, that is, the ways the regions interact, involve various stakeholder groups and redraw their unique collaborative boundaries (Sirtori et al., 2019; Hassink et al., 2019; Chen & Hassink, 2020). First, the Covid-19 crisis brought to the forefront the complexity of these areas, as they are affected by different restrictions or regulations. Second, digitalization and platform-based collaboration open new areas and governance types for interactions among regions and various stakeholder groups (Florek-Paszkowska et al., 2021). Digitalization spans administrative boundaries and integrates regions on substantive rather than administrative grounds. These governance firms are often captured as concepts of entrepreneurial ecosystems, social entrepreneurial ecosystems, and territorial financial ecosystems (Wurth et al., 2021; Gancarczyk & Konopa, 2021; Thompson, 2018; Łasak, 2022). They gather resources and various stakeholder groups, such as local governments and industrial actors, sharing their resources and experience. Third, policies and regulations affect regional cross-border collaborations, such as the recent trend toward internationalization of smart specialization strategies of EU regions (Foray, 2018, 2019, 2020). From the above, a socioeconomic analysis of these areas from a multidisciplinary approach is needed.

A bibliometric exploration of Scopus’ documents about ‘Euroregion’

A search of the publications about Euroregions located in Scopus was performed. The access link was https://www.scopus.com/search/form.uri?display=basic#basic. The survey was conducted on the 27th of July 2022 and it was decided to focus on the key term of this Special Issue – ‘Euroregion’. Thus, it was searched for the set of publications with 'Euroregion' in the title of the document, the abstract, or the set of keywords. Of course, any other search possibilities will give lower frequency results (e.g. 'Euroregion' and 'Innovation'). With this exercise, it is only intended to offer a current bibliometric image around the concept of 'Euroregion', without detracting from the potential offered by the use of software such as Vosviewer that also allow exploring the network of co-authorships or co-citations (which will remain as significant further research). So, 333 documents filling the above criteria were found.

Thus, in this mainly exploratory exercise, special attention was paid to dimensions such as the possibility of accessing documents, the year of publication, the scientific area assigned to the documents, their type, the most receptive journals, the universities and countries of affiliation of the authors, as well as the funding agencies identified in the papers.

Regarding the possibility of access, 86 of the 333 documents are open access. This value makes it possible to verify that a significant percentage of documents tracked by Scopus can be consulted without the need for a subscription associated with paid licenses.

The most frequent type of document is the Article (272), followed by the Book Chapter (32), the Conference Paper (18), the Review (6) and the Conference Review (2).

If the evolution of the year of publication of the documents is considered, it is observed that the first document dates from 1989. Since 1995, there have always been (at least) three documents published following the identified criteria. In 1998, there was a special high number if considering the past track (12 documents), while in 2004 another relevant number of publications was also reached (13). Finally, since 2009, only once there have been no more than 9 publications per year. Thus, it seems evident that since 2009 there has been a growing trend in the number of publications around the term of ‘Euroregion’, with a maximum of 26 documents in the year 2020.

The most frequent keywords in these documents were: Euroregion (75), Cross-border cooperation (72), Europe (59), Euroregions (54), and Cross-border relations (50).

The main scientific areas of publications are, in descending order, the Social Sciences (238), the Earth and Planetary Sciences (76), the Environmental Science (67), the field of Business, Management and Accounting (39), as well as the area of Economics, Econometrics and Finance (38). Therefore, despite the concept of 'Euroregion' having an administrative foundation, it is seen how the identified publications are also located in diverse scientific areas, which demonstrates the potential of the concept as a spatial unit of reference observation for many areas of knowledge.

Galician universities are the affiliation spaces most frequently associated with the authors of documents identified by Scopus with the central term of ‘Euroregion’. Thus, the University of Vigo has 17 documents and the University of Santiago de Compostela has 10 documents. WSB University –Dabrowa Gornicza closes the trio with the highest frequency, also with 10 documents. As a result, the countries of affiliation of the authors of the documents identified with the highest representation in the screening are Poland (56 documents), Spain (49 documents), the Czech Republic (40), Germany (29), and France (23).

The most frequent languages in the body of the document are: English (241), French (29), German (26), Spanish (21), and Polish (7).

The main funding agency for the documents identified is the European Commission (24 documents). The following agencies are European Regional Development Fund (18), Interreg (5), Ministerio de Economia y Competitividad (4) and the Foundation for Science and Technology (3).

Following this exploratory section, three potential discussion notes arise to conclude it.

The first note refers to the suspicion of the dependence of the number of publications on key moments related to European Regional Policy. As denoted, and considering that, on average, an article takes between one and two years to be published after its draft version has started, the key antecedent moments can be looked for the years identified as a structural break in the evolution of the number of publications, namely the years 1998, 2004 and 2020. Thus, the period before 1998 saw a significant increase in the funds allocated to the European Regional Policy. The year 2004 was part of the so-called Lisbon Strategy, which significantly increased the cohesion dimension of European regional policy. Finally, 2020 is a year of transition between the Europe 2020 Strategy and the regional planning assigned to the period 2021-2027. As such, it does not seem to be reprehensible that such reinforcements of strategy in European regional policy have contributed to investigations focused on the concept of Euroregion.

The second note recovers the diversity of scientific areas of the identified articles. As it has pointed out, the insight goes in the sense that the concept of Euroregion has already gone beyond the meaning of spatial administrative unit within the European Policy and it is also used in works in scientific areas such as Environmental Sciences or the Earth and Planetary Sciences. This evidence demonstrates that research teams understand how administrative boundaries are not able to seal off research problems in territories delimited by historical borders but that, regardless of whether these phenomena are considered social or physical-environmental, they are problems shared in the areas currently considered as Euroregions by the different resident communities.

Finally, the third note highlights the role of universities such as the Spanish universities of Vigo and Santiago de Compostela (belonging to the Northwest Euroregion of the Iberian Peninsula). The presence of research groups focused on European regional problems, the existence of thematic seminars and congresses, and the stimulus provided by specific funding help to achieve a more evident result for some academies. However, the significant role of regional development agents of these universities cannot be neglected in the dedication evidenced in the set of publications focused on the concept of Euroregion.

Contents of the Special Issue 'Euroregions in Perspective: Old Issues and New Challenges for Cooperation'. An overview

This special issue focusing on Euroregions is composed of eight articles selected through a rigorous review process in accordance with the journal's editorial guidelines. The topics vary both at the territorial level and in the specific focus of the analysis, providing a comprehensive and complementary view of the general topic.

The work by Cristina García Nicolás, entitled Euroregions: Cooperation, Cohesion and Resilience , aims to place Euroregions in the current context, facing the need for similar levels of governance that favour decision-making on both sides of the border, and the legal obstacles in relation to mobility and economic activity that the restrictions derived from Covid-19. This analysis addresses the definition of Euroregions in a context of cross-border cooperation that favours the economic, social and territorial dimensions of cohesion.

Rui Alexandre Castanho and José Cabezas Fernández are the authors of the work entitled The Phenomenon of Cross-Border Cooperation in the Iberian Peninsula: A Retrospective Look at the Luso-Spanish Euro-cities , which aims to set a retrospective look at Portuguese-Spanish Euro-Cities. In this sense, they analyse how these cities have grown and how it is their relevance for the common and sustainable development of the border regions there are inserted. A novelty this work brings is to show how these second-generation CBC projects (Euro-cities) evolved and could be the new trend and catalyst for sustainable territorial development in border regions.

The work by Valerià Paul Carril, entitled The Cross-Border Minho River Strategy 2030: Spatial Planning for the Minho River Lower Valley , focuses on this strategy by discussing with the general theoretical and conceptual spatial planning principles and, more specifically, in the wake of those of the spatial planning developed in cross-border regions. In addition, a constant tension between two areas within the River Minho European Grouping of Territorial Cooperation (EGTC) is examined.

The work entitled Analysis of a value chain in cross-border integration. The agri-food chain value in the shared Minho , written by Carlos M. Fernández-Jardón Fernández and Xavier Martinez Cobas, aims to analyse a specific cross-border value chain (agri-food) in the area of the River Minho, by estimating the gross value added of the value chain by municipalities in both parts of the territory.

Ana María López-Villuendas and Cristina del Campo are the Authors of the work entitled Analysis of economic Convergence in the Euroregion Galicia-Norte de Portugal in the 1980-2019 period , with the objective of contributing to the general discussion of real convergence between the regions that form a cross-border region, in a context of intense cooperative relations, such as the Euroregion Galicia-Norte de Portugal.

The work by Serafin Pazos-Vidal, entitled “Emptied Spain” and the limits of domestic and EU territorial mobilization , provides a narrative since 2016 of the failed efforts of territorial mobilisation of a number of actors to frame the priorities and mapping of both Spain´s Demographic strategy and EU Cohesion Policy for the purposes of rent-seeking.

Vincent Pijnenburg, in his work entitled Contemplations on and practical guidelines for cooperation in the Dutch-German borderland , by analysing the Dutch-German cooperation in recent decades, aims to provide some practice-oriented principles for cross-border cooperation (CBC) which could contribute strengthening its impact. The author assumes that the attention for CBC is still volatile, depending among other things on political and economic trends.

The work entitled Tourism as an engine for the Euroregion sustainable development. Insights from Euroregion TATRY , byVanda Maráková and Lenka Dzúriková, aims to identify whether the development of tourism in the selected Euroregion (TATRY) is sustainable in the future. For this purpose, they examine statistical data and documents describing cooperation activities to analyse the current state of tourism development in the TATRY Euroregion, and if the further development of tourism in the TATRY Euroregion addresses the principle of sustainability.

The guest editors thank all the contributors and believe that this thematic issue broadens our understanding of the developments and challenges of the European interregional and cross-border collaboration. It can also be informative for practitioners and policy-makers who shape regulatory frameworks and public support programs for Euroregions. They also are grateful to the Iacobus 2021 Program of the European Association for Cross-Border Cooperation Galicia North Portugal, which supports a stay in which the idea of this Special Issue was raised and the first steps were undertaken.