Some journals now only publish this data electronically on the Internet. Supplemental information also contains other voluminous material not appropriate for the main body of the article, like descriptions of routine procedures, derivations of equations, source code, non-essential data, spectra or other such miscellaneous information. Review articles do not cover original research but rather accumulate the results of many different articles on a particular topic into a coherent narrative about the state of the art in that field. Review articles provide information about the topic and also provide journal references to the original research. Reviews may be entirely narrative, or may provide quantitative summary estimates resulting from the application of meta-analytical methods. Data papers are articles dedicated to describe datasets. This type of article is becoming popular and journals exclusively dedicated to them have been established, e.g. Scientific Data and Earth System Science Data. Video papers are a recent addition to practice of scientific publications. They most often combine an online video demonstration of a new technique or protocol combined with a rigorous textual description. The formats of journal articles vary, but many follow the general IMRAD scheme recommended by the International Committee of Medical Journal Editors. Such articles begin with an abstract, which is a one-to-four-paragraph summary of the paper. The introduction describes the background for the research including a discussion of similar research. The materials and methods or experimental section provides specific details of how the research was conducted. The results and discussion section describes the outcome and implications of the research, and the conclusion section places the research in context and describes avenues for further exploration. In addition to the above, some scientific journals such as Science will include a news section where scientific developments (often involving political issues) are described. These articles are often written by science journalists and not by scientists. In addition, some journals will include an editorial section and a section for letters to the editor. While these are articles published within a journal, in general they are not regarded as scientific journal articles because they have not been peer-reviewed. Electronic publishing Electronic publishing is a new area of information dissemination. One definition of electronic publishing is in the context of the scientific journal. It is the presentation of scholarly scientific results in only an electronic (non-paper) form. This is from its first write-up, or creation, to its publication or dissemination. The electronic