Personally I have learned from the following PN references:
1. Parenteral & Enteral Nutrition by J. Rambeau
2. ASPEN Parenteral Nutrition Handbook by Ayers et al.,
3. Subscription of American Journal of Parenteral & Enteral Nutrition and Nutrition in Clinical Practice by ASPEN
4. Applied Therapeutics (Koda Kimble) & Pharmacotherapy (DiPiro) Chapters on Nutrition
My personal opinion: To learn PN, 70% of knowledge & Experience come from the mentor/preceptor and 30% from references. I strongly recommend the PGY-2 Nutrition Support residency