N. Subrahmanyam and B. Lal.A textbook of sound, (for B. Sc. (pass, honours and subsidiary), engineering students of Indian universities and IAS examinations).Vikas,1974.
U. S. Navy Dept. Naval Air Development Center.Acquisition, reduction, and analysis of acoustical data：an unclassified summary of Acoustical Working Group.Pa.,1974.
ed. by R. E. Barnhill and R. F. Riesenfeld.International Conference on Computer Aided Geometric design ( 1974 : Utah )：Computer Aided Geometric design.Academic Pr.,1974.
