TY  - BOOK
AU  - Hammock,Robert C
AU  - Owings,Ralph S.
TI  - Supervising instruction in secondary schools / 
T2  - McGraw-Hill series in education
U1  - 373 18
PY  - 1955///
CY  - McGraw-Hill
PB  - London ; 
KW  - School supervision, Secondary
ER  -