Dear Ondrej Follow this link to an HTML-ised version of article on 80-90 years worth of BAAVSS data for V Boo, and fourier type analysis thereon, as appeared in a JBAA article earlier this year. http://vsnet.telf-ast.demon.co.uk/00042b.html V Boo has been "doubly periodic" throughout the century. Further, if memory serves V Boo is definitely on a longish list of "doubly periodic" variables as "found"/revealed by AAVSO folk in their investigations... ...said list appears in an article in ESA-SP402 "Hipparcos Venice 97", which bits of can be accessed via the ADS, but I can't remember that article title at the moment. Mattei and Foster are two of the authors. [Sorry for not being any clearer on that ref... ...there are so many variables my brain is begging to leak! I dunno how folk like TK (J) manage to remember it all! ;^)] Cheers John John Greaves, UK