Dictionary of Economics (also known as Oxford Dictionary of Economics)
Oxford Reference Online (2017, 5th ed)
The New Palgrave Dictionary of Economics Online Living Edition, regularly updated
(2008, 2nd ed) online and in print: HB61.N49 1987 t (4 vols)
Annual Reviews (select subject via Journals A-Z at top)
Topical essays critically review the primary research literature in the field.
Guide to Economic Indicators: Making Sense of Economics
HA29. E28 2011, 7th ed (SL Books)
Elgar Companion to Post Keynesian Economics
HB99.7. E522 2003 (SL Books)
Handbooks in Economics Series (Elsevier books via ScienceDirect)
(Online and Print - call number varies)
ebook reference series covering the various branches of economics. 110 plus volumes contain review articles written and edited by the leading authorities in the field.
In Omni search "handbooks in economics" or the title of the individual volume.
Or search ScienceDirect
Some titles in the series are:
Handbook of Econometrics
Handbook of International Economics
Handbook of Mathematical Economics
Handbook of Monetary Economics