1. INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
2. Department of Physics, University of Crete, Voutes, 70013 Heraklion, Greece.
3. Institute of Astrophysics, Foundation for Research and Technology-Hellas, PO Box 1527, 71110 Heraklion, Crete, Greece.
4. School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Rd., E14NS London, UK.
5. Laboratoire Lagrange, UMR7293, Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, Boulevard de l’Observatoire, 06304, Nice Cedex 4, France.
6. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland.
7. Dipartimento di Fisica, Universitá degli Studi di Torino, Via Pietro Giuria 1, I-10125 Torino, Italy.
8. Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305, USA.
9. Centre for Astrophysics Research School of Physics, Astronomy and Mathematics University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK.
10. American Association of Variable Stars Observers, 49 Bay State Road, Cambridge, MA 02138, USA.
11. Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile.
12. Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain.