As is revealed in xxx ,which provides illustration about ...
没有不对.这是一个很好的开头.我很喜欢.
或者
把 is 改为 has been ：
As has been revealed in xxx ,the item which provides illustration about ...
会更雅致,但这是次要的.
（顺便一提,如果你谷歌 “As was previous stated" 或类似短语,你会发现这是很正确的说法.）