Alternating from 1 to x and vice versa. - Valle, Andrea; Lombardo, Vincenzo; Vogel, Hairi (2007)

The Virtual Electronic POEM (VEP) Project. - Lombardo, Vincenzo; Arghinenti, Andrea; Nunnari, Fabrizio; Valle, Andrea; Vogel, Heinrich H.; Fitch, John P.; Dobson, Richard W.; Padget, Julian A.; Tazelaar, Kees; Weinzierl, Stefan; Benser, Sebastian; Kersten, Stefan; et al. (2005)