TY  - BOOK
AU  -  Hammock,Robert C.
AU  -  Owings,Ralph S.
TI  -  Supervising instruction in secondary schools / 
U1  -  373.11 
PY  - 1955///
CY  -  New York : 
PB  -  McGraw-Hill, 
KW  -  School supervision, Secondary
ER  -