The rich frequency spectrum of the triple-mode variable AC And
  Fourier analysis of the light curve of AC And from the HATNet database reveals the rich frequency structure of this object. Above 30 components are found down to the amplitude of 3 mmag. Several of these frequencies are not the linear combinations of the three basic components. We detect period increase in all three components that may lend support to the Pop I classification of this variable. 
G. Kovacs, G. A. Bakos, and J. D Hartman
astro-ph.SR