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Many writers, on starting a text with appreciable mathematical content, will prepare for themselves an overfull sequence of formulae, derivations and proofs; then they use this as a secure home base for the further processes of selection, abbreviation, highlighting and verbal comment, which constitute the more creative parts of authorship, and whose success determines the reader's pleasure and profit from the final product. Apart from its general introductory parts, this book reads like an almost straight transcription of such an auxiliary framework.
G. Barton (Fri,) studied this question.