As Andrew Norman wrote, in a letter published in this book on page 113,  You flit freely back and forth between prescriptivism and descriptivism. 
( ( As ( ( Andrew Norman ) ( ( wrote , ) ( in ( ( a letter ) ( published ( in ( ( this book ) ( on ( page 113 ) ) ) ) ) ) ) ) ) ) ( , ( You ( ( ( flit ( freely ( ( back and ) forth ) ) ) ( between ( ( prescriptivism and ) descriptivism ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (NNP Andrew) (NNP Norman)) (VP (VBD wrote) (, ,) (PP (IN in) (NP (NP (DT a) (NN letter)) (VP (VBN published) (PP (IN in) (NP (NP (DT this) (NN book)) (PP (IN on) (NP (NN page) (CD 113))))))))))) (, ,) (NP (PRP You)) (VP (VBP flit) (ADVP (RB freely) (RB back) (CC and) (RB forth)) (PP (IN between) (NP (NN prescriptivism) (CC and) (NN descriptivism)))) (. .)))
Andrew Norman has five letters which are published in this book.
( ( Andrew Norman ) ( ( has ( ( five letters ) ( which ( are ( published ( in ( this book ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Andrew) (NNP Norman)) (VP (VBZ has) (NP (NP (CD five) (NNS letters)) (SBAR (WHNP (WDT which)) (S (VP (VBP are) (VP (VBN published) (PP (IN in) (NP (DT this) (NN book))))))))) (. .)))