[Scientific writing: the choice of references].

Only "acceptable" references can be cited, i.e. references that the reader can find easily. Only published work must be referenced, and the author must only cite those papers he or she has actually read. These should be avoided, as they are always difficult to obtain. Conference abstracts are published either in the conference report handed to participants alone, or in special issues of journals. Only the latter should be cited, when necessary. References to oral presentations are not accepted. References to personal communications should not be included in the list of references. The author cited must have given express permission. "Secondhand" references, i.e. those the author has not taken time to read yet quotes nonetheless, are prohibited. Manuscripts submitted for publication should not be cited. Articles accepted for publications can be referenced as "In press; "name of journal"".