Penna, C.V.The planning of library and documentation services. Second edition revised and enlarged by P.H. Sewell and Herman Liebaers.Unesco manuals for libraries, 17. Unesco, Paris, 1970.
3.
Sewell, P.H.The development of library services; the basis of their planning and assessment. J. Librarianship, 2 (I) January 1970 , 33-42.
4.
Withers, F.N.Review of: American Association of State Libraries. Standards for library functions at the State level. J. Docum. , 26 (3) September 1970, 267-269.
