Using Books or magazines to raise your bed to a five degree angle is simple, inexpensive and far more practicle than having them sitting gathering dust in your bookcase.
I prefer to use medical and science books. Seems a shame to waste all that paper, when they all need to be rewritten to take into account that our circulation is driven by gravity.
Here we can honestly state that the scientific and medical literature, really does support inclined bed therapy, and no one can say otherwise!