Quotations of and allusions to ancient texts will often carry more than one reference; e.g. ‘1: Diogenes Laertius, I.24=11 A 1’.
A bold arabic numeral accompanies the more important quotations, which are inset from the margin: that numeral documents the position of the text in this book. Thus the quotation labelled ‘1’ is the first text of substance that I quote.
The source of every citation is specified: usually the author’s name alone is supplied, and further information must be gleaned from Diels-Kranz; fuller details are given for more familiar authors (e.g., Plato and Aristotle), and also in cases where the citation is not printed in Diels-Kranz. Full citations follow the usual canons; and abbreviations of all book titles are explained in Appendix A. (But note here that ‘fr.’ abbreviates ‘fragment’; that titles of the Greek commentaries on Aristotle are abbreviated by prefixing ‘in’ to the abbreviated titles of Aristotle’s works; that SVF, in citations of the Stoics, refers to H.von Arnim’s Stoicorum Veterum Fragmenta; and that FGrH, in citations of certain historians, refers to F.Jacoby’s Fragmente der Griechischer Historiker.) Thus ‘Diogenes Laertius, I.24’ refers to Chapter 24 of Book I of Diogenes’ only work, the Lives of the Philosophers.
Almost all the texts I refer to are printed in the standard source book on early Greek philosophy, Die Fragmente der Vorsokratiker by Hermann Diels and Walther Kranz. References to Diels-Kranz, in bold type, cite chapter, section, and item (but the chapter number is omitted wherever it can be divined from the context of the citation). Thus ‘11 A 1’ refers to the first item in section A of Chapter 11, ‘Thales’. Chapters in Diels-Kranz are usually divided into two sections: section A contains testimonia; section B contains fragments. Sometimes, where no fragments survive, B is missing; sometimes a third section, C, contains ‘imitations’. In the case of Chapter 58, ‘The Pythagorean School’, a different principle of division is adopted. Readers should be warned that the B sections contain many texts whose status as genuine Presocratic fragments is disputed. (Citations bearing on Heraclitus, Empedocles, Melissus and Zeno sometimes carry an additional bold figure reference: those references are explained in the notes to the chapters in which they are used.)
Finally, where a numeral in plain type is suffixed to a bold type reference, it serves to indicate the line (or occasionally section) of the text in question. Thus ‘31 B 115.9’ refers to line 9 of 31 B 115.
All that is, I fear, somewhat cumbersome; and it makes for unsightliness. But I can discover no more elegant method of citation which is not annoyingly inconvenient.