References should be listed at the end of the paper in alphabetical order. Articles in preparation or articles submitted for publication, unpublished observations, individual communications, etc. should not be included in the reference list but should only be mentioned in the article text (e.g., C.k. Palmer, Harvard University, United States, individual communication). Journal names are abbreviated according to Chemical Abstracts. Authors are responsible for the accuracy and completeness of their references and for correct text citation.