(subclass Source PureTwopole) | engineering.kif 520-520 | 资源 是 纯双极 的 subclass |
(subclass AcrossVariableSource Source) | engineering.kif 524-524 | 跨变量来源 是 资源 的 subclass |
(subclass ThroughVariableSource Source) | engineering.kif 528-528 | 通过可变来源 是 资源 的 subclass |