TY  - DATA
AU  - Leigh, Robert Barrington.
AU  - Liu, A. C. F.
TI  - Hungarian problem book IV 
T2  - Problem Books, 
SN  - 9781614444053 (online)
PY  - 2011///
CY  - [Washington, D.C.]
PB  - Mathematical Association of America
KW  - Mathematics
UR  - https://www.ams.org/prb/023
ER  -