Analysis of short term price trends in daily stock-market index data
  In financial time series there are periods in which the value increases or decreases monotonically. We call those periods elemental trends and study the probability distribution of their duration for the indices DJIA, NASDAQ and IPC. It is found that the trend duration distribution often differs from the one expected under no memory. The expected and observed distributions are compared by means of the Anderson-Darling test. 
H.F. Coronel-Brizio, A.R. Hern\'andez Montoya, H.R Olivares S\'anchez,   E. Scalas
q-fin.ST