TY  - BOOK
AU  - Vacca,John R.
TI  - THE WROLD'S 20 GREATEST UNSOLVED PROBLEMS
SN  - 0131426435
U1  - 500 
PY  - 2005///
CY  - 
PB  - Prentice Hall Ptr, New Jersey
KW  - Sscience -- Miscellanea
KW  - Research
ER  -