Rasse IV de Gavre, heer van Ath, Chièvres, Gavre en Lidekerke et van Eskaerde - Sources for sons?

and Walter van Gavere

8 RAZO 1156 (VL, 1, no. 250, p. 147) -t before 1190 (Les Bouteillers, Pr., no. IV, pp. 6-7).
nob. (VL, 1, no. 333, p. 185 (1180); Gislebert de Mons, p. 141). "Optimas" (SNFurnensis, pp. 87-88); "baro" (Afllighem, p. 177), "primas" (Liber fund. Drongen, fo 8 VL ).
Lord of Chievres (Cambron, 1, p. 354 (1186) ).
Knight (Gislebert de Mons, pp. 72, 104, 111).
Butler (of Flanders) (St. Bavon, no. 54 (1171); RA. Mons, cartul. 64, fo 9 VL• 10 ro (1176, April 6) ).
Crusade 1177 (Duchesne : Bethune, Pr., p. 42; G. de Liedekerke : Gavre, p. 65)?
x Mathilda (Cartul. Ninove, CCF. II, no. XXIII, p. 97 (1166)) of Liedekerke ? of Ghent ? of Aalst ? (G. de Liedekerke : Gavre, pp. 56-59).
Children:
-Razo v (Ename, p. 58 (1181) ).
-Razo (Les Bouteillers, Pr., no. IV, pp. 6-7).
-Walter ?
-Roger?
-Just?
-Giles ? (G. de Liedekerke: Gavre, p. 69).
Warlop, 810

The info that Roger and Josse le Nattier are the same person comes from a different source. The name btw comes from his ability to weave mats after he became a monk.

So, no primary sources to quote?