1. Theoretical nursing: development and progress;Meleis,1997
2. Four generations of nurse theorists in the US;Hall;Vard I Norden,1997
3. Beck D. Spiral dynamics integral. Available at: www.spiraldynamics.net. Accessed Jan. 7, 2002
4. A theory of everything;Wilber,2000
5. An integral approach to medicine;Astin;Altern Ther,2002