ORTEP-III may be cited via its user manual.
Michael N. Burnett and Carroll K. Johnson, ORTEP-III: Oak Ridge Thermal Ellipsoid Plot Program for Crystal Structure Illustrations, Oak Ridge National Laboratory Report ORNL-6895, 1996.
The citation for OR TEP-II is:
Carroll K. Johnson, OR TEP-II: A FORTRAN Thermal-Ellipsoid Plot Program for Crystal Structure Illustrations, Oak Ridge National Laboratory Report ORNL-5138, 1976.
Page last revised: July 25, 1996