## 4 Discussion and Conclusions  
As has been reflected in previous studies, AR has positioned itself as an emerging technology that yields a set of benefits in training processes. As a result, there is a need to explore its state of affairs in higher education from the perspective of WoS. With regard to the bibliometric indicators defined in this study, starting with its scientific performance in ARHE, it is shown that ARHE is not abundant, although its production is not recent, since its beginnings date back to 1997. From then until now, its production has been inconstant due to the combination between productive years and recess years, with three different observable moments. In the first moment, dating from 1997 to 2008, production was not high (7.97%), and there was no trend, being instead irregular. During a second period, from 2009 to 2014, production was more extensive (21.74%), albeit with similar trends to the first period. The last period, which appears from 2015 to the present, was the most productive (70.29%), with an upward trend (since the volume of publications is growing every year). These results are similar to those revealed in the literature, although the periods of higher production differ slightly, being established in 2012-2016 [35] and in 2015-2017 [33]. With regard to language, the one used by scientists to present their research is English, as found in other studies [33]. The studies are presented via communication and articles, evenly, with the first being slightly more common--results that are consistent with other studies that also add a paper as a type of relevant study [3], with quantitative studies being the main methodological choice [38]. For sources of origin, \"INTED proceedings\" (3.62%) and \"EDULEARN proceedings\" (2.36%) are the most common. The areas of knowledge where research on ARHE is presented are diverse, since there is an even production between \"education educational research, computer science, and engineering\", which determines the thematic variety of the established field of study. Figure 7: Strategic authoring diagram. For the institutions, the Spanish are the pioneers of this type of study, since they take the top positions (highlighting the Universidad de La Laguna (3.08%) and the Universidad de Sevilla (2.72%)). It is worth noting that [PERSON]. (11 works), [PERSON]. (9 works), [PERSON]. (10 works), and [PERSON] (7 works) have provided the most research in this area and even the first two have the highest h-index (four and three, respectively), although they are not the most relevant in this subject. Instead, [PERSON], [PERSON], and [PERSON] are the most relevant by its position in the diagram. The references that have the highest number of citations are [45; 46] with 194 and 114 citations, respectively; these scientific texts are the ones that articulate the basis of the current state of research. Studies in the scientific literature have also found that Spain is one of the countries with the highest production in this field (18.66%) [33], but Taiwan is also an important booming country [37]. In contrast, other studies cite the University of Science and Technology of Taiwan as the main institution and [PERSON] and [PERSON] as the most important authors [37]. Regarding the continuity of keywords between contiguous periods, it is revealed that only 28% of the keywords are repeated between both periods. The increase in the volume of keywords of the second period (n = 1165) with respect to the first (n = 703) stands out. Therefore, 970 new keywords are established in the second period. The evolution of ARHE has not been regular nor has it settled on a single theme; instead, it has evolved over time and is currently in the process of establishing a solid line of research.