Słownik polsko-angielski EXETER Copyright © http://www.kastor.strefa.pl.
it is a well-known fact/common knowledge
nic nie ~ nobody knows
Uniwersalny słownik polsko-angielski Copyright by Wydawnictwo HaraldG (aut. Andrzej Kaznowski)
pred it is known
nic nie wiadomo - there is no knowing
o ile mi wiadomo - for all I know, as far as I know
o ile mi wiadomo, to nie - not to my knowledge
nigdy nie wiadomo - you never know
Wojskowy słownik polsko-angielski Copyright by Wydawnictwo HaraldG (aut. Tadeusz J. Grzebieniowski)
v imp it is known; nic nie ~ there is no know-ing; o ile mi ~ as far as I know, for all I know
Nowoczesny słownik polsko-angielski
it is known jak ~ as is known