General descriptions of the relevant literature：A considerable amount of literature has been published on X。 These studies 。。。。There is a large volume of published studies describing the role of ...。The first serious discussions and analyses of X emerged during the 1970s with .。。。The generalisability of much published research on this issue is problematic.What we know about X is largely based upon empirical studies that investigate how .。。.During the past 30 years much more information has become available on 。...In recent years, there has been an increasing amount of literature on .。..A large and growing body of literature has investigated .。。.General reference to previous research/scholarly activity （usually more than one author)Many historians have argued that .。。. (eg。 Jones, 1987; Johnson， 1990； Smith， 1994）Numerous studies have attempted to explain 。..。 （for example, Smith ， 1996; Kelly, 1998; Johnson, 2024）Recent evidence suggests that 。。.。 (Smith, 1996; Jones 1999； Johnson, 2001)Recently, in vitro studies have shown that T。thermophylus EFTu can .。。. （Patel et al.， 1997; Jones et al。， 1998）.Surveys such as that conducted by Smith (1988） have shown that 。.。。Several attempts have been made to .。.。 （Smith, 1996; Jones 1999; Johnson， 2001)Several studies have revealed that it is not just X that acts on 。.... （Smith， 1996; Jones 。.。。Several biographies of Harris have been published。 Smith presents an 。..。 account, whilst Jones ....Several studies investigating X have been carried out on .。。.Data from several sources have identified the increased morbidity and mortality associated with obesityPrevious studies have reported .。.. (Smith， 1985； Jones， 1987; ...
