Teares before bedtime

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Levels in the structure of works

Apologies for not replying earlier - I seem to have missed some of the discussion. I agree with the structure proposed. Suggest that “Collection” here is used to denote works which are related either by the composer (Wagner’s Ring Cycle), or by being frequently recorded/performed together (Bach’s Well Tempered Klavier Book 1). IMO the use of this “Collection” relationship versus the Work/Series relationship needs clarification. Perhaps the latter should be reserved for Opus (Bach BWV series)…