The face as a whole has been giving me problems of late. This is due to not doing much reference and study. So I decided to start doing some studies of the oh so obvious, dead center feature we all love and love to hate. The nose. They can be pretty tricky to draw, especially if you don't know what makes them up. Thankfully there are a number of anatomy for artists books out there that go over it. Some more helpful than others.
Peck is helpful in that he gives some visual shorthand for drawing the nose. There are also the anatomical plates that go into detail about the bones of the skull.
I rather enjoy John Sheppard's diagrams. They're line drawings that detail the anatomy with rather clear labels. But what I really like is the page full of all kinds of noses. Very useful study.
Unfortunately, as helpful as Loomis is, in the pass I made there wasn't all that much for the nose. I think more of it is covered in general facial anatomy.