David, T. S., J. S. David, C. A. Pinto, J. Cermak, V. Nadezhdin and N. Nadezhdina (2012) Hydraulic connectivity from roots to branches depicted through sap flow: analysis on a Quercus suber tree. Functional Plant Biology, 39: 103-115.
http://dx.doi.org/10.1071/FP11185
Nadezhdina, N., M. W. Vandegehuchte and K. Steppe (2012) Sap flux density measurements based on the heat field deformation method. Trees – Structure and Function, 26: 1439-1448.
http://link.springer.com/article/10.1007%2Fs00468-012-0718-3