Greater Weapon Specialization( Player's Handbook v.3.5, p. 95)
[Fighter Bonus Feat, General]
Choose one type of weapon, such as greataxe, for which you have already selected Weapon Specialization. You can also choose unarmed strike or grapple as your weapon for purposes of this feat. You deal extra damage when using this weapon.
fighter level 12th, Greater Weapon Focus with selected weapon, Proficiency with selected weapon, Weapon Focus with selected weapon, Weapon Specialization with selected weapon,
Weapon Supremacy (PH2) ,
You gain a +2 bonus on all damage rolls you make using the selected weapon. This bonus stacks with other bonuses on damage rolls, including the one from Weapon Specialization (see below).
You can gain Greater Weapon Specialization multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon. A fighter may select Greater Weapon Specialization as one of his fighter bonus feats (see page 38).