1)      Only reference lists — not entire articles — should be pasted into the simple-text query form.

2)      Journal, book chapter, and book references will be processed by the simple-text query resolver
         to retrieve DOIs. Other types of references (e.g., conference proceedings) will be ignored.

3)      References should be reasonably well formed but need not follow any specific editorial style.

4)      Reference lists should be alphabetical (unnumbered lists) or sequential (numbered lists).

5)      Each reference in the list must begin on a new line (although each reference can span multiple
         lines).

6)      Lists that have hard line breaks inserted mid-reference are supported; however, the simple-text
         query resolver works best when hard returns are placed only at the ends of references.

7)      Special characters such as accented letters or Greek symbols are supported. However,
         pasting special characters into a web form can distort them, so it's best to provide plain ASCII
         text or the form default of Latin 1. ISO and Unicode entities (e.g., é or é) are
         also supported. If you need to paste in text using other character sets, please contact CrossRef.

8)      Reference lists with annotations should have the annotations removed. For example:

                   29. S. L. D'Hondt, M. A. Arthur, Paleoceanography 10, 123 (1995).
                   An excellent description of the problems we discuss in our paper.

                   30. K.-H. Hoffmann, D. J. Condon, S. A. Bowring, J. L. Crowley,
                   Geology 32, 817-820 (September 2004).

9)      References that include multiple citations — often seen in chemistry and physics journals – are
         supported. For example:

                    [6] [a] T. Hudlicky, G. Seoane, T. Pettus, J. Org. Chem. 1989, 54,
                    4239. [b] T. Hudlicky, C. H. Boros, E. E. Boros, Synthesis 1992,
                    174. [c] G. Butora, A. G. Gum, T. Hudlicky, K. A. Abboud, Synthesis
                    1998, 275. [d] J. Zezula, T. Hudlicky, I. Ghiviriga, Coll. Czech. Chem.
                    Commun. 2001, 66, 1269.