Soderblom, David R.; Clements, Sandra D. (April 1987). "Chromospheric and Transition-Region Emission from Young Solar-Type Stars in Clusters, Kinematic Groups, and the Field". The Astronomical Journal. 93: 920–937. Bibcode:1987AJ.....93..920S. doi:10.1086/114378.
Soderblom, David R.; Clements, Sandra D. (April 1987). "Chromospheric and Transition-Region Emission from Young Solar-Type Stars in Clusters, Kinematic Groups, and the Field". The Astronomical Journal. 93: 920–937. Bibcode:1987AJ.....93..920S. doi:10.1086/114378.