Each of these can be found from certain sources, for example:

Similarly, certain sources of information are more reliable than others.

My own dreams, and certain other sources of information, have told me a great deal which you still find obscure.

Usually the player is able to disable certain light sources.

A dwarf plant with yellow flowers appeared in my garden a year or two ago, from no certain source.

The plant was a certain source of significant new carbon dioxide emissions.

Accordingly, he shows up as such in certain sources.

However, certain sources state that they married in 1796.

Norshteyn has been known for refusing funding from certain sources.

The prospect: research has enabled us to find certain renewable sources of energy.