## 2 Theoretical Background  
### Literature Gap  
As part of the preliminary literature research into the issues of logistics operators' activities in omni-channels and network coordination, the authors conducted a review of the SCOPUS article database. The analysis focused on extracting articles thematically related to business, management, and accounting sciences. The time frame for the searched articles extended to August 2023 in the SCOPUS database. The authors, in the first step, created an overview of the papers connected with keywords (of papers, authors, and journals) in the range of the following: \"network coordination\", \"network governance\", \"omni-channel\", \"3 PL\", \"logistic operator\", or \"logistic service provider\". Based on the SCOPUS database, 1796 articles were extracted, for which analyses were conducted using the VOSviewer tool. This is a tool used for creating clusters, networks of connections, and relationships between topics appearing in various scientific works. VOSviewer is employed as a tool to support the literature analysis in various scientific disciplines [18; 19; 20]. Figure 1 depicts the connections of keywords and the formed clusters for the mentioned guidelines. Figure 1: Clusters and connections between the main keywords based on SCOPUS elaborated on VOSviewer. Based on the main keywords connection map it could be concluded there is no connection for every examined keyword. However, the connection with the main clusters is also shown in Figures 2-4. The cluster of network governance is linked with the supply chain, implying that this theme is frequently addressed in publications related to supply chain sciences, potentially involving the description of mechanisms governing flows. However, this cluster is not associated with either omni-channel or logistics operators, suggesting that these themes are not considered together. Network coordination and logistics coordination do not form a visible cluster on the map, which is attributed to the relatively low percentage of works addressing such topics. The 3 PL cluster is connected, among others, with the AHP methodology, indicating that authors frequently examine the issues of third-party logistics providers using this method. Additionally, 3 PL is also strongly linked to the supply chain, but not in the context of considering 3 PL actions within the scope of network governance or network coordination. The omni-channel cluster is strongly connected with the supply chain, but similar to the previous case with 3 PL, it does not associate with the topics related to network governance or network coordination. Omni-channel exhibits connections with 3 PL as well, but these associations are not as frequent and well established in the literature as in the case of other, stronger connections depicted in the provided figure. Also, based on the analysis of search phrases in titles, keywords, and abstracts, it can be indicated that the topic related to network coordination is relatively prevalent. A total of 396 articles were found in the database that were related to this subject, although the majority of them were associated with computer science (63.89%) and engineering (67.17%). Articles strictly linked to business, management, and accounting that could address the issue of network coordination concerning collaborating networks of enterprises were encompassed in 57 articles. Similarly, the situation is similar in the case of \"network governance\", which often addresses a similar topic. The number of articles here is greater than in the previous case (279 articles), and the upward trend for new articles on this subject is more noticeable (Figure 5). Figure 2: Connection with main cluster “network governance” elaborated on VOSviewer. According to the SCOPUS database, the number of articles related to network coordination was highest in the year 2022, with a total of 10 articles (17.54%) indexed in the SCOPUS database in this subject area.