Comparing nocturnal eddy covariance measurements to estimates of ecosystem respiration made by scaling chamber measurements at six coniferous boreal sites - Lavigne, M.B.; Ryan, M.; Anderson, D.E.; Baldocchi, D.; Crill, P.M.; Fitzjarrald, D.R.; Goulden, M.; Gower, S.T.; Massheder, J.M.; McCaughey, J.H.; Rayment, M.; Striegl, Robert (Journal of Geophysical Research D: Atmospheres, 1997)