The text of the following papers by Dr. Gerard K. O’Neill are available here:
The World’s Energy Future Belongs in Space
An Alternative Plan for the U.S. Space Program

The following SSI conference papers are also available:
Sustainable Water in Closed Biosystems: Preliminary Design Considerations

by William J. Jewell – 2001

Information Infrastructure for Long Term Habitation of Space Environments
by Jay Thomas et. al. – 2000

Architecture Options for Space Solar Power
by Seth D. Potter et. al. – 1999

Inhabiting Artificial Gravity
by Theodore W Hall – 1999

Solar Blade Heliogyro Nanosatellite Development
by Richard Blomquist – 1998

Sub-Kilogram Intelligent Tele-Robots for Asteroid Exploration and Exploitation (SKIT)
by Alberto Behar et. al. – 1996

Initial Study of the Separation of Aluminum Oxide and Calcium Oxide from Lunar Simulants
by Rudolf Keller – 1996

Microwave Launches of Small Payloads
by Leik N. Myrabo – 1994

Magnetism of Lunar Soils
by R. R. Oder – 1992

Technology for Human Space Settlement