Literature on the Zero Lower Bound
The possibility of such an impediment has been mentioned over the years by McCallum (2000) and possibly others.[1] In the recent past, Paul Krugman and Michael Woodford have provided their views about the topic. Paul Krugman stated at the beginning stages of the ZLBP in the US itself that the monetary policy won’t be able to resolve this situation, and unconventional methods will be necessary to tackle it.[2] Speaking on the topic, Michael Woodford remarked that in a zero lower bound, the ideal thing to be done is for the central bank to bridge the output gap by spending liberally on stimulating effects. [3]
http://macroeconomicanalysis.com/macroeconomics-wikipedia/zero-lower-bound-problem/