Map of Plato's Republic

I'm currently trying to write a lecture on Plato's Republic. Since the (later) division of the work into ten books isn't particularly helpful, I came up with this map - thought I'd post it here for reference, in case anyone else finds it useful.

I	327a-54c	Argument with Cephalus, Polemarchus & Thrasymachus
II	357a-68b	Challenge to Socrates
II	368c-76d	Initial founding of good city; division of labour
II-III	376d-402c	Early education of Guardians; censorship of poetry
III-IV	402c-27c	Upbringing of the Guardians, inc. physical regimen
IV	427d-34c	Account of virtues, inc. justice
IV	434d-44e	Division of individual soul (psyche)
V	449a-72e	Prescriptions for the Guardians, inc. family life and war
V-VI	473a-504d	Rule of philosophers; true philosophers distinguished from lovers of sights and sophists
VI	504e-11e	The Form of the Good: the Sun and Divided Line
VII	514a-21c	The Cave
VII	521c-41b	Education of the Guardians
VIII-IX	543a-76b	Deviant constitutions (timarchy, oligarchy, democracy, tyranny) and corresponding men
IX	576b-92b	Comparing the happiness of just and unjust men
X	595a-608a	Exile of imitative poetry
X	608b-21d	Immortality of the soul and afterlife rewards