# Development and Future Trends of Digital Product-Service Systems: A Bibliometric Analysis Approach
## 4 Discussion  
In order to arrange the dispersed literature on digital PSS and offer a framework for future research in a field that lacks defined boundaries, this study employs bibliometric analysis. In response to RQ1, this study names the significant authors, nations, and sources influencing digital PSS research. According to this research, authors from South and East Asia (specifically China, Hong Kong, and Singapore) are the most prolific in the area, followed by those from Scandinavia. (i.e., Sweden, Finland, and Norway). Finally, the remaining top 20 most productive writers in the area of digital PSS are authors from Italy and Serbia. The construct of the 20 most prolific authors is altered when compared to earlier studies of traditional PSS. Scandinavian and British writers are the most prolific in traditional PSS. In both research groups (i.e., traditional and digital PSS), only two authors,  
Figure 8: Digital PSS thematic map. [PERSON] and [PERSON], are the most productive [33]. It seems that there are also ten clusters of authors who have close ties to one another. The strongest three clusters are from the authors mentioned above. The most frequently cited articles, on average, come from UK authors rather than those from the most productive nations. The network study of cross-national cooperation is similar to the author's origin. With 8 of the top 10 most prolific sources, Elsevier is the most successful publisher in this field. One source from Springer and one source from MDPI Publisher are then presented. This research provides a brief content analysis in reaction to RQ2 and lists the keywords that appear the most frequently. The keyword analysis shows that smart products, Product-Service Systems, product design, and servitization are the most frequently occurring keywords in the existing literature in this field. However, the future trends show that digital servitization as a keyword will construct the top five keywords in the digital PSS field. The content analysis based on keyword co-occurrence demonstrates the paper development process from traditional PSS and their transfer to digital PSS through the influence of digitalization on PSS performance and the presence and structure of PSS ecosystems. Furthermore, some novel subjects derived from keyword co-occurrence analysis indicate that blueprint and design thinking as a creative technique might be used to conduct a thorough examination of the creation of digital services in the PSS industry. Furthermore, these two methodologies (blueprinting and design thinking) are becoming more popular in service engineering, and it will be interesting to see how manufacturing organizations will use them in the future. Additionally, the brief content analysis shows that topics such as digital servitization, service business models, digital technologies and innovations, design of smart PSS, and manufacturing transformation processes are the most frequently researched areas in the most cited papers in the field of digital PSS. Furthermore, data reveal that the 10 most referenced publications span the years 2017 to 2020. Finally, the top five subject fields identified through the analysis of the research articles used in this study are engineering (53%); business, management, and accounting (50%); computer science (47%); decision sciences (21%); and environmental science (11%). This research involves a detailed analysis of the content that is provided in the area of digital PSS in answer to RQ3. The [PERSON] model, [PERSON] model, and [PERSON] model are commonly used for PSS transformation. The [PERSON] model defined the first phase of the transformation of manufacturing firms as the shift from a product- to a services-oriented business [58]. The new transformation brought about via the adoption of digital technologies was from traditional to digital PSS, as defined by the [PERSON] model [59]. Additionally, the [PERSON] model illustrates how Industry 4.0 as a whole alters the business model in industrial companies with customer-focused digital PSS [17].