## 2 Methodology  
The analysis of the publication trend of scientific articles has become the standard unit that allows the quality of the knowledge-generating process and its impact on the scientific environment to be qualified. In this way, it is feasible to evaluate the state of the art and prospects of the topic under investigation [36]. Bibliometric studies are based on statistical analyses of specific data collected from the review of databases, focusing on publication indicators such as articles, authors, citations, keywords, etc., which are susceptible to analysis [37]. Recently, researchers from multiple disciplines have extensively adopted bibliographic methodologies that combine bibliometric analysis and systematic literature reviews to describe the development of a concept in their research areas [38; 39; 40]. Particularly, bibliometric analysis has gained remarkable popularity within the domain of business research, including business strategy [41], marketing [42], management [43], human resources [44], etc. This popularity can be attributed to the valuable information that can be extracted from these types of studies, e.g., extension of research activity, publication output, collaboration patterns, dissemination of knowledge, etc., as well as its potential to uncover emerging trends, handling a huge volume of unstructured scientific data, or the cross-disciplinary pollination of data science to business research [45]. The first integration of LM and SS methodologies was in the late 1980s; however, it was the publication of the book _Lean Six Sigma: Combining Six Sigma Quality with Lean Speed by [PERSON]_ (2002), which significantly raised the appeal of LSS as a combined framework for organizations [46]. Thus, the present bibliometric analysis and literature review covers the period from 2002 to 2022 in order to understand the evolution of LSSM over this time. Initially, the searches were carried out in two of the most relevant databases: Scopus (Elsevier) and Web of Science core collection (Clarivate). To follow the current trend and state of LSS applied to the manufacturing of chemicals, it is crucial to begin with a global perspective and progressively deepen in more specific concepts. Thus, the search was mainly organized into three categories: (i) the implementation of LSS in any sector (manufacturing and non-manufacturing environments); (ii) LSS implementation in manufacturing companies; and (iii) LSS adopted in the manufacturing of chemicals. In this regard, the following sequence of terms was used to search the article titles, abstracts and keywords: \"Lean Six Sigma\", \"Lean Six Sigma Manufacturing\", \"Lean Six Sigma Manufacturing Chemicals\" and \"Lean Six Sigma Manufacturing Chemical Industry\" (Figure 1). The study excluded certain types of articles, such as editorial notes, reports, prefaces, theses, conference articles, and working papers, and included those that were published in peer-reviewed academic journals. Additionally, there was no language restriction. These exclusions ensured a focused and rigorous analysis of the relevant literature. Following this scrutiny, abstracts of the collected articles were further analyzed for the LSSM adoption framework, factors contributing to its success or failure and case studies on LSS applied to the manufacturing of chemicals. Finally, a thorough analysis of these studies was carried out. Based on the search results, Scopus was selected as the database for this study. The methodology is illustrated in Figure 2.  
Figure 1: Scientific publications between 2002 and 2022 as a function of the database employed. A bibliometric software, i.e., VOSviewer (developed by [PERSON] and [PERSON] from the Centre for Science and Technology Studies [47]), was employed for bibliometric mapping. Different graph-based maps were constructed to visualize bibliometric networks that include journals, researchers and publications based on citation, bibliographic linkage, co-citation and co-authorship relationships.