"That you have written" refers to the book of those in between.
Because usually we can just refer to the book, we've got pages.
Three stars over their heads refer to the book itself.
There is much further evidence in this case for which I refer the reader to the book itself.
His answers to the other 19 are far more complicated, so you will have to refer to the book.
For the argument on which these conclusions are based we refer to the book itself.
Physicians at Duke refer to your book all the time.
He didn't need to refer to the book; these were facts known to any scholar of the period.
The Dutch press refers to the book as a laughing mirror.
They may also receive recordings of any radio reviews, television programs and so on, which refer to his book.