Designing 4th order Butterworth Multiple feedback bandpass filter
Just above Table 16-2:


  ...with a1and b1 being the second-order low-pass coefficients of the desired filter type.
  To simplify the filter design, Table 16
  –
  2 lists those coefficients, and provides the 
  α
   values


The fourth order band-pass filter in that example is built from two partial second order filters. This method is called staggered tuning.

This means that the coefficients a1 and b1 of Table 16-2 are second order coefficients, and not fourth order coefficients.

Table 16-5. shows low-pass coefficients. Compare with Table 16-1:



Thus, you can use the Table 16-2 and staggered tuning to design your fourth order band-pass filter.