Peer review assists the editor in making editorial decisions and through the editorial communications with the author may also assist the author in improving the paper. Any selected reviewer who feels unqualified to review the manuscript or knows that its prompt review will be impossible should notify the editor and excuse himself from the review process. Reviews should be conducted objectively. Personal criticism of the author is inappropriate. Referees should express their views clearly with supporting arguments. Any manuscripts received for review must be treated as confidential documents. They must not be shown to or discussed with others except as authorized by the editor. Reviewers should identify relevant published work that has not been cited by the authors. Any statement that an observation, derivation, or argument had been previously reported should be accompanied by the relevant citation. A reviewer should also call to the editor's attention any substantial similarity or overlap between the manuscript under consideration and any other published paper of which they have personal knowledge.