@ ubaid
After seeing this question in 2012 paper,i think we should be more specific in answering such question.

Give a precise but comprehensive account of major schools of thoughts in administration. Also compare and contrast Taylor's Management and Human Relations.


As you have mentioned,there are four school of thoughts given by FPSC in syllabus,so only these schools must be included in the answer of above mentioned question.
School of thoughts as such are not available in "dr.Sultan's book".I have found them in VU's notes of Public administration.you can easily find these notes on google.Just type "Introduction to Public administration-MGT111.pdf" in google.


hope this will work

Regards