Spectroscopy of BL Cam - Observations
  The star BL Camelopardalis (GD 428, GSC 04067-00471, V=12.92, B=13.1), is a SX Phoenicis pulsating variable showing a high amplitude variability (300-350 mmag), with a very clear period of 56.3 min, that has being recently studied by Fauvaud et al. (2010). They show that the observed variability is due to a clear and single pulsation, as expected for these type of pulsators. It was discovered as a variable star on 1976 by Berg and Duthie (1977). 
M. Alvarez, R. Michel, L. Fox-Machado, J.P. Sareyan, S. Fauvaud, G.   Tovmassian
astro-ph.SR