A DOI is a unique and persistent identification number for the digital object with which it is associated. DOIs are commonly assigned to online scientific articles. Many journals now require DOIs to be included in references. More about DOI.
Go to the DOI Resolver page, type in the DOI string and click on "Submit". If you are on campus, the DOI Resolver will take you to the "Find it at GSU" page. This page not only shows you the citation of the article, but also shows you if we have the article electronically or in print. If we don't have it in either form, an ILL link will show up so you can request it through Interlibrary Loan.
Go to the CrossRef Simple Text Query page, paste your reference in the box provided and click on "Submit". It will provide the DOIs if available.
Note: Some articles don't have a DOI.
E.g. The 2008 Impact Factor for a Journal:
A = the number of times articles published in 2006-7 were cited in indexed journals during 2008
B = the number of articles, reviews, proceedings or notes published in 2006-7
HENCE: Impact Factor (IF) = A/B
E.g. A 2008 journal with an Impact Factor (IF) of say 3.333 means that on average, each of its 2006 and 2007 articles was cited 3.333 times in 2008.
Impact factors have criticism e.g., limited subset-only uses articles cites by 9000 journal (approx), some disciplines are not completely covered, baised towards English–language journals, short snapshot of a journal, it is an average, includes self-citations, includes only citable articles in the denominator of IF equation), editors can skew data by increasing number of review articles (bring in more citations) or increase number of news items (may not be cited).
2. h-Index from Scopus