1. 1. Garcia AD , Thomas DR. Assessment and management of chronic pressure ulcers in the elderly. Med Clin North Am 2006; 90: 925-44.
2. 2. Black J , Baharestani M , Cuddigan J , Dorner B , Edsberg L , Langemo D , Posthauer ME , Ratliff C , Taler G. National pressure ulcer advisory panel's updated pressure ulcer staging system. Dermatol Nurs 2007; 19: 343-9, quiz 50.
3. 3. Nixon J , Cranny G , Bond S. Pathology, diagnosis, and classification of pressure ulcers: comparing clinical and imaging techniques. Wound Repair Regen 2005; 13: 365-72.
4. 4. Ohura T , Takahashi M , Ohura N Jr. Influence of external forces (pressure and shear force) on superficial layer and subcutis of porcine skin and effects of dressing materials: are dressing materials beneficial for reducing pressure and shear force in tissues? Wound Repair Regen 2008; 16: 102-7.
5. 5. Bennett L , Kavner D , Lee BK , Trainor FA. Shear vs pressure as causative factors in skin blood flow occlusion. Arch Phys Med Rehabil 1979; 60: 309-14.