University repositories are an ordinarily open-access database of the research and publication productions of an institution. Grey literature is the unpublished, non-commercial, hard-to- find information that organizations such as professional associations, research institutes, think tanks, and government departments produce. The most comprehensible sources of reference are the encyclopedias for the selection of the topic as well as the preparation readings after the topic selection. One of the sources that are appealed in scientific studies is the statistics. The statistics utilized by researchers lose their up-to-dateness as soon as the new statistics are published. Periodicals are more widely known as journals. They are the major information source of prior research literature. Periodicals are published a number of times a year and are sent to subscribers including the libraries. The journals which report the research findings are the most significant ones.