In recent years, citations are increasingly used as performance indicators of individuals, research groups, departments,and even institutions. In many places, it is used for allocation of research funding, hiring of academic personnelandeven for career progression, promotion or tenure[1,2] . It is always presumedthat citations in some way measure the scientific impact of a study or researcher. It has beenused as one of the core indicators in many university rankings for decades too. However, in reality, what citations actually measure and how it relates to the scientific quality has always been a controversial topic as citation rates are determined by many factors, starting from technical issues to researcher bias. Many technical problems associated with recording and retrieval of citation data such as incomplete journal coverage in the database, expensive on-line database access, bias of database, not-inclusion of books as source items in the database, solely first-author retrieval in some databasesetc. can influence directly on the citation rate.