Even if he signs itself with three different names on the cover (La flauta de Bartolo, Porky & Rasputòn) the author is only one, named Carlo Vila i Vila, vd. https://www.lambiek.net/artists/v/vila_carlos.htm .

The use of three names is intended as a joke, a play on trinity and the book title itself.

Each name is chosen also as a play-word by itself, together with the drawing accompanying it.
(Rasputòn : an hispanized Rasputin)
(Porky, or Porquy : quite possibly a ref. to "Porky's" US comedy series)
(La flauta de Bartolo i.e. "The flute of Bartolo" : "flute" here is a byword for "penis", so the whole name means "Bartolo's dick" without saying it explicitly)