Analyses of strong motion earthquake accelerograms : volume- 4 Fourier amplitude spectra, part I : accelerograms II-I12-8 through II-I139 / California Institute of Technology. 

 - Pasadena, Calif. : Research Laboratory 
 - 86 p. 
 - Report ; no. EERL 74-101 / CALTEC, Earthquake Engineering R-esearch Laboratory .