## 2 Materials and Methods
### Bibliometric Analysis  
As said, with the aim of analysing and studying scientific activity in the use of AR for the dissemination of cultural heritage, we have carried out a bibliometric analysis on the Scopus database. To retrieve data, we performed the following queries (on 17 December 2020): topic = (TITLE-ABS-KEY (\"augmented reality\" AND \"cultural heritage\")); topic = (TITLE-ABS-KEY (\"augmented reality\" AND \"cultural heritage\" AND \"dissemination\")); topic = (TITLE-ABS-KEY (\"augmented reality\" AND \"architectural heritage\")); topic = (TITLE-ABS-KEY (\"augmented reality\" AND \"architectural heritage\" AND \"dissemination\")).  
The total number of documents found for the first query (relating to \"augmented reality\" with \"cultural heritage\") was 693. This number was reduced to 46 when the term \"dissemination\" was added. There were only 25 documents for the query with \"architectural heritage\" and this number dropped to 5 when \"dissemination\" was added to the search. Figure 2 shows two plots with the number of documents sorted by year. The first aspect to highlight is that this is a relatively recent field of research (the first document appears in 1999), in which activity has clearly increased in recent years, reaching a peak in 2019 with a total of 118 papers for \"cultural heritage\". When the term \"dissemination\" is added to the search, the maximum value also happens in the same year. Besides, it can be seen that the first works that relate to both concepts are not published until 2005. Later still does the association between \"augmented reality\" and \"architectural heritage\" occur, and it is not until very recently that the \"augmented reality\" was used for the dissemination of architectural heritage, as seen in Figure 2b.  
Figure 2: Life cycle of the publications relating “augmented reality” with (**a**) “cultural heritage” (in blue) and “dissemination” (in orange); (**b**) “architectural heritage” (in blue) and “dissemination” (in orange).  
Table 1 shows the type of document for each query in percentages. In all cases the largest number of documents corresponds to publications at conferences, except for documents dealing with augmented reality applied to the dissemination of architectural heritage.  
When analysing the number of documents per subject area, it is worth pointing out that the contributions from the fields of computer sciences, engineering, and mathematics are the most numerous for \"cultural heritage\". In the query concerning \"cultural heritage\" and \"dissemination\", the first field is still computer sciences, but social science and arts and humanities become the second and third most important fields. These three fields are also the first when searches incorporate the terms \"architectural heritage\", and \"architectural heritage\" and \"dissemination\" (Figure 3).  
Finally, as shown in Figure 4, it is interesting to note that most of the production is European, with Italy clearly at the top of all the queries made in the database. It is also important to highlight the third position of Spain, along with Greece, in the queries concerning \"cultural heritage\" and the second position of Spain, together with Canada, Colombia, and Malaysia, for the queries concerning \"architectural heritage\", which gives an idea of the level of interest in these fields that exists in the authors' country.