## 3 Materials and Methods
Therefore, this research is based on this framework and the trends of the literature that have emerged in recent years, with an extensive effort to identify the gaps and problems related to critical operational conditions. In order to facilitate problem identification and research directions, the following questions were asked:  
**RQ1. **: _How can logistics companies effectively integrate Industry 4.0 technologies with existing systems and ensure interoperability?_  
**RQ2. **: _What are the critical steps and conditions required for the successful implementation of a business model in logistics?_  
**RQ3. **: _What are the potential financial and competitive advantages for organizations that successfully implement Industry 4.0 applications in their logistics operations?_  
Figure 2: The steps of the bibliographic review process. Step 2: Search strategy  
When searching for literature sources, what must be determined from the beginning is what search strategy will be used and how the research questions will be converted into keywords. In this case, research questions RQ1, RQ2, and RQ3 have been formulated based on our own research rationale for the research topic in the corresponding literature survey, which aimed to clarify the dominant trends regarding what prevails in logistics business models, in line with data from the Industry 4.0 era. The variety of relevant keywords was firstly identified and recorded, and secondly, search strings were developed from identified keywords, which dominate the concept of trends concerning a business model in logistics in the respective search channels. Google Scholar and Academia were used as search channels in the international literature. The selection was based on the fact that these two search engines provided the most results with the greatest relevance to the research topic and methodology. The next step was to clearly define the search strings from the identified bibliography keywords drawn from the search. To select the appropriate strings, we filtered the data collected from the initial literature search and came up with the concepts that have the most relevance to the objective of our study, which is to investigate the critical steps and assumptions that take place in a logistics business model, always combined with the concept of Industry 4.0. The search strings used in the search bases were \"Innovative Business Models in Industry 4.0\". Terms with various variations were then used, such as \"Logistics 4.0\", \"Digital Transformation in Industry 4.0\", \"Human Resources in Industry 4.0\", and \"Quality in Industry 4.0\". By applying the search strings to Google Scholar and Academia online search databases, the total number of papers retrieved was 684. After studying these 684 papers, we ended up including those most relevant to the Industry 4.0 era and that are also included in our research philosophy. The total number of papers included in this methodological step amounts to 213. Step 3: Selection and evaluation of papers  
After searching for bibliographic sources in the aforementioned search engines, the process of selecting and evaluating the works was carried out, with the primary objective of excluding duplicates and works of low quality or relevance to the topic. Then, to determine the theme of the papers, their abstract and keywords were thoroughly read. In order to make the results more targeted in the search for the problem under consideration, some restrictions such as journal publishers, publication dates, and language were set. In this context, it was decided to consider papers only from reputable publishing houses of well-known journals (a high index of academic and research credibility) such as MDPI, Elsevier, Taylor & Francis, Emerald, IEEE Advancing Technology for Humanity, etc. At the same time, because the topic is still in an early research stage, most of the works on the critical conditions and functions for the implementation of Industry 4.0 in logistics enterprises are reported from 2019 onwards.