Table 2.

Contributions of the reviews in the secondary sources.

No.	Year	Ref.	Object of Study
1	2005	[11]	This is sustainable energy development in the Chinese countryside and discusses the main problems of sustainable energy development during different periods.
2	2006	[12]	This studies regional and agricultural policy in Spain from 1985 to 2006.
3	2011	[13]	This presents the analysis and evaluation of biomass production based on energy crops in Poland in 2007 and 2009.
4	2014	[14]	Efforts to build an association at local level to manage biomass production are being studied in the absence of an institutional plan and public investment.
5	2016	[15]	This studies rural entrepreneurship and identifies that in the period of analysis a basic theoretical construct of rural entrepreneurship that has focused mainly on developed countries is recognised.
6	2017	[16]	This studies the connections between agriculture and tourism by improving sustainable development in tourism as well as in rural communities and the agricultural sector.
7	2017	[17]	This study was conducted in Zimbabwe to investigate factors influencing the sustainability of rural water supply systems.
8	2018	[18]	Local knowledge of the territories is studied, where development practices and policies based upon counteracting demographic decline are identified.
9	2021	[19]	This corresponds to the applicability of Geographic Information System (GIS) tools for the implementation of sustainable development principles in rural areas.
10	2022	[20]	Identifies which factors have been taken into consideration in the expansion of entrepreneurship and renewable energy technologies in rural areas of developed countries.