Phrases with «kinds of sources»

It had to be some new kind of source, some new type of star that we had never seen before. (discovermagazine.com)
What kinds of source material do you use? (hyperallergic.com)
All these effects depend, ultimately, on how much soot is in the air, which, in turn, depends on the many different kinds of sources of soot all over the world. (theguardian.com)
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