I'm just writing my bachelors thesis and I need to reference to a book for an in-depth derivation of something.
The concluding sentence in this work is just perfectly formulated, there is no way of making it shorter or more precise. I wonder whether I should write something like
As  points out, it can be shown that the enhancement in the second-harmonic power is given [...]
With the bold text being the quote from the book or reformulate the sentence, making it somewhat less precise? Is this even enough attribution when copying the sentence verbatim or do I need to put quotation marks?