R. P. Gabillard

Detection of underground cavities with an electromagnetic method between soil surface and drill-hole (in French) : Bull Liaison Lab Ponts Chaussees, N92, Nov–Dec 1977, P68–73

J. P. Dubus, R. P. Gabillard, R. Bavandi, 1977 .

DETECTION OF UNDERGROUND CAVITIES BY ELECTRO-MAGNETIC METHOD BETWEEN THE SOIL SURFACE AND THE BOREHOLE

M. Rat, J. P. Dubus, R. P. Gabillard, 1977 .