Strongly disagree! If used as described it has not been broken. Only if letters in the same sentence are reused (if your lazy) or you limit yourself to a single page (lazy again). The permutations are huge.
2,7,16,73,45,67,11,42,5,3,51,48,2,6,35,88 is "AAAA" encrypted. All you have to know is the book I used, which number is the page, which number is the sentence, and which is the character. (I didn't use paragraph I'm lazy it also is usually a smaller number and could be spotted.)I also changed the sequence somewhere in the string.