No CrossRef data available.
Published online by Cambridge University Press: 14 August 2015
Photometric and spectroscopic observations were made by Oskanian and Terzan (1974) on the 40-cm telescope at Byurakan Observatory and by Morguleff et al. simultaneously at the 80-cm photometric telescope and the Coudé Spectrograph of the 152-cm telescope of the Observatoire de Haute Provence.