The first close-up of the "flip-flop" phenomenon in a single star H. Korhonen, S. V. Berdyugina, K. G. Strassmeier and I. Tuominen A&A, 379 1 (2001) L30-L33 Published online: 15 November 2001 DOI: 10.1051/0004-6361:20011359