This is the 867th most frequent Polish word.
źródeł
"Źródeł" means "sources" in English (genitive plural form of "źródło").
In this sentence, 'źródeł' again appears in the genitive plural, contextualized within the notion of corroborating information sources.
Nie powinniśmy korzystać z niepewnych źródeł.
We should not use unreliable sources.
Here, 'źródeł' is used to reference 'springs' or origins of water, showcasing its application to natural contexts.
Woda pochodzi z naturalnych źródeł.
The water comes from natural springs.
Here, 'źródeł' is the genitive plural form of 'źródło', and it denotes 'sources' in the context of informational materials.