Table 3. Main proposals for the improvement of the loose coupling between software units.

RQ-1 Proposals based on		Quantity	References
SOA		10	Green (2013), Voican (2012), Cuadrado et al. (2008), Herrera Quintero et al. (2010), Devi et al. (2014), Kim (2009), Hong & Wen-yue (2010), Chen (2009), Coronado-García et al. (2011), Deng et al. (2008)
Web Services		7	Risimic (2016), Beer & Hassan (2018), González & Ortiz (2013), Monfort & Hammoudi (2009), Huang & Zhang (2010), Ji (2009)
Microservices		5	Dragoni et al. (2017a, 2017b), Parizi (2018), Shadija, Rezai & Hill (2017), Gómez (2018)
Middleware		3	Antipov, Antipov & Pylkin, 2016, Cranefield & Ranathunga (2013), de los Ríos (2016)
Models of Metadata		2	García & Montoya (2011), Muñoz & José (2009)
Library and Framework		2	Weyns & Georgeff (2009), Ma, Tang & Wang (2009)