不必说，这一切都是从无线电广播报道中搜集来的第二手信息。

All this, needless to say, had been culled second-hand from radio reports.

他一定是通过第二手或第三手资料了解那些哲学家的。

He must have come to know those philosophers through secondary or tertiary sources.

更多古代资源的英译本；其中包括有用的拉丁文碑铭和剧场的照片集；少许古罗马的第二手旧作品。

More ancient sources in translation; useful collections of photos of Latin inscriptions and theatres inter alia; a few old secondary works on ancient Rome.