title: Comment on "Opening optical four-wave mixing channels with giant enhancement using ultraslow pump waves".
authors.affiliation: Dipartimento di Fisica, Universitá di Siena, Via Roma 56, I-53100 Siena, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Buffa
authors.forename: Stefano
authors.initials: S
authors.lastname: Cavalieri
authors.forename: Marco V
authors.initials: MV
authors.lastname: Tognetti