It is learned… 据悉...
It is understood… 据了解...
It is authoritatively learned…自权威方面获悉...
According to an anonymous source 据一位不愿透露姓名的消息灵通人士说……
A source who asked not to be identiried disclosed… 据一位不愿透露姓名的消息灵通人士说……
Foreign wire services were quoted/cited as saying…援引外国通讯社的消息说……