Retraction Note: Intracytoplasmic morphologically selected sperm injection versus conventional intracytoplasmic sperm injection: a randomized controlled trial - Giovanni Battista La Sala; Alessia Nicoli; Eleonora Fornaciari; Angela Falbo; Ilaria Rondini; Daria Morini; Barbara Valli; Maria Teresa Villani; Stefano Palomba (BMC, 2017)