The more sources the better
Every researcher aims to have a standardized and uniform study when a study will be replicated or repeated for various reasons. 
The number of 
accounts and evidential support of your thesis must be consistent and be
 sufficient and succinct to the topic of study. These reasons and 
evidential support should claim proximate with the pronounced 
experimentation and variables which will be studied. In sense, the more 
accounts and sources the better is your study, the greater it will stand
 out and present itself. This is important for every thesis paper or 
dissertation since these accounts provides and explicitly discusses the 
studies that have been undertaken before which can greatly influence the
 current study's credibility and reliability.