## 1 Introduction
They also raise the importance of understanding by engineers of both IT and OT cybersecurity landscapes in order to be able to develop frameworks for detection and control/learning system design that integrate the best policies from both domains to create workable solutions. The increased understanding of OT security importance has led to the rapid growth of research in that area and attempts to systemize the research performed in the review articles. In the defined period from 2018 to 2024, we identified 32 review articles. On the other hand, it is worth mentioning that only a small part of them concentrate on OT only [1; 8; 10], while the rest still use more specific ICS, SCADA, and CPS terms. These mentioned articles [1] concentrate on OT (with expansion to ISC) for construction sites only, including threat modeling and general cybersecurity questions, not paying attention to OT protocols, related ML/DL methods, and datasets. The authors of [8] mainly concentrated on OT in the chemistry industry only. This publication is not a systematic literature review,as it mainly presents main definitions, problems and possible solutions. The main audience is not cybersecurity specialists but chemical industry engineers, for whom this article could be a good starting point for understanding the problem. A rather similar approach was used in [10], where analysis was narrowed to OT security in Smart Grids. It also pays the most attention to the awareness of the problem and provides an in-depth review of attacks and possible protection mechanisms. In a wider context of ICSs/SCADA, Smart Grids is the most intensively researched topic and is also discussed in [11; 12]. There are a number of review articles, which provide reviews on research on malware or specific malware type detection in IIoT/SCADA/ISC systems, such as [13; 14; 15]. One more trend that can be seen from the research articles demonstrates the increasing amount of research being performed in the sphere of machine and deep learning applications in threat and attack detection, namely [3; 6; 16; 17], once again concentrating not specifically on OT, but more on SCADA/ICSs. An additional trend that can be seen from the research articles demonstrates the increasing amount of research being performed in the sphere of machine and deep learning applications in threats and attacks. The number of review articles on SCADA/ICSs for specific fields except Smart Grids, is relatively low. We found just one review article which summarizes research about attacks against medical CPS [18] and one about the security of electric vehicle charging systems [19], while the majority of review articles are stuck with the general analysis of SCADA/ICS threat landscape, vulnerabilities, protection mechanisms, and open issues: [5; 20; 21; 22]. Three of the mentioned review papers [1; 5; 20] used SCOPUS as the main search tool for appropriate articles. Summarizing it could be said that despite the number of review articles published in the reviewed period, the majority of them are not concentrating on OT but rather on more common SCADA/ICS topics; some of them try narrowing the analysis field to a specific topic (Smart Grids, Medical Equipment, anomaly detection, etc.). In this paper, we conduct a systematic bibliometric study of current research patterns in OT threats, threat detection, and security insurance measures proposed or discussed in scientific literature by obtaining data from the Web of Science (WoS) database. We aim to include a wide range of high-quality articles without narrowing them to a specific field.