Second order section digital Bandpass Does anyone have a ressouce on how I can calculate second order section bandpass coefficients?

What I tried allready:

I used following formulas from the Book Electronic Circuits (U.Tietze, Ch. Schenk) for the Lowpass:
My coefficients match exaclty (difference is max 2e-14) with the second order sequions of MATLAB for the same lowpass.

For a bandpass filter I used following formulas:


The results differ quite alot from MATLAB, expecially if the order is higher than 2.
Also I dont think I can apply the formulas direcly for second order sections because the coefficients only depend on constant values.
So it seems that the formulas from the textbook for the bandpass are not accurate. 

I used following approach to calculate second order sections given an analogue filter lowpass. As an example following code displays the coefficients for a 4th order bandpass, calculated from a second order lowpass protopye.


Paramters

fs = 1000;
fs1 = 200;
fs2 = 300;
w1 = 2*pi*fs1/fs;
w2 = 2*pi*fs2/fs;
Omega1 = 2*tan(w1/2);
Omega2 = 2*tan(w2/2);
syms s z Om2 Om1 a1 b1 A0
% apply LP to BP transformation
G_s_BP = subs(H_s, s, (s^2 + Om1*Om2)/(s*(Om2 - Om1)));

Start with analogue transfer function H_s

H_s = A0 / (1 + a1*s + b1*s^2);
% apply LP to BP transformation
G_s_BP = subs(H_s, s, (s^2 + Om1*Om2)/(s*(Om2 - Om1)));

Digital conversion with bilinear transformation

G_z_BP = subs(G_s_BP, s, 2*(( z - 1)/(z + 1)));
% order polynomial such that coefficients can be read out
coeffs_z = collect(G_z_BP, z)

Those coeffs_z are very similar to the ones given by the iowahills software
The band-pass filter coefficients then can be calculated with any analogue low-pass prototype, just enter numerical values on read out coefficients from coeffs_z