TY  - BOOK
AU  - Patilla, Peter
TI  - Guide to good Maths: Subtracting 
SN  - 0-7534-0158-4
AV  - TR(GS 510.7 P27 1990
PY  - 1990///
CY  - London
PB  - Kingfisher
KW  - Subtraction
ER  -