R.T. VAN BALEN; J.M. VERWEIJ; J.D. VAN WEES; H. SIMMELINK; F. VAN BERGEN; H. PAGNIER. Deep subsurface temperatures in the Roer Valley Graben and the Peelblock, the Netherlands - new results. Netherlands Journal of Geosciences, v. 81, p. 19-26, 1 Mar. 2002.