Aging reduces complexity of heart rate variability assessed by conditional entropy and symbolic analysis - Takahashi, Anielle Cristhine de Medeiros; Porta, Alberto; Melo, Ruth Caldeira de; Quitério, Robison J; Silva, Ester da; Borghi-Silva, Audrey; Tobaldini, Eleonora; Montano, Nicola; Catai, Aparecida Maria (Internal and Emergency Medicine, 2012)