To the best of my knowledge, there are no such rigid rules on the minimum or maximum number of references necessary in an article. It is the responsibility of the author to give due credits to the materials he refer for his study. Good journals insist that only the articles that are cited in the content matter should be included in the reference list. It is better to include the articles that are relevant to the present study in the reference list.
It depends upon your target journal. Usually they have maximum number but never mention required minimum number. Usually for case reports it can be from 10 to 15, for original articles from 30 to 100, for review articles up to unlimited! However each journal has their own reference criteria. Better to follow their recommendations. Good Luck!
There is no such rule. However, less number of references reflects the originality of the research work. More number of references reflect the popularity of the topic.
In general, in standard journal publications the number of references is more.