"dubious sources" refers to information or references that are untrustworthy, unreliable, or questionable in their accuracy or credibility. It suggests that the sources may not be reliable or worthy of believing. Full definition
Good research can, and is, done with funding from dubious sources. (realclimate.org)
Smaller pet stores are starting to jump on board, too, selling pet products and hosting adoptable shelter animals, instead of selling animals from mills or other dubious sources. (thedodo.com)
Every now and then a rumour comes along from a completely dubious source, and despite the fact it screams «made up story», said rumour quickly starts picking up traction online. (flickeringmyth.com)