Transcutaneous electrical nerve stimulation (TENS) reduces pain and postpones the need for pharmacological analgesia during labour: a randomised trial - Santana, Licia Santos; Gallo, Rubneide Barreto Silva; Ferreira, Cristine Homsi Jorge; Duarte, Geraldo; Quintana, Silvana Maria; Marcolin, Alessandra Cristina (Journal of Physiotherapy, 2016)