diff --git a/applications/lofar2/model/pfb_os/README.txt b/applications/lofar2/model/pfb_os/README.txt
index 011e8e527f7a9c931c0aa558bcd8e995450ccd87..2dc39328c1b7bc3b93fb676e66831f753bd00d6d 100644
--- a/applications/lofar2/model/pfb_os/README.txt
+++ b/applications/lofar2/model/pfb_os/README.txt
@@ -13,7 +13,7 @@ Author: Eric Kooistra, nov 2023
   can not exactly reproduce the actual LOFAR1 coefficients, therefore these
   are loaded from a file Coeffs16384Kaiser-quant.dat
 
-* Try low pass filter design methods using windowed sync, firls, remez [3]
+* Try low pass filter design methods using windowed sync, firls, remez [4]
   The windowed sync method, firls leased squares method and remez method all
   yield comparable results, but firls and remez perform slightly better near
   the transition band. The firls and remez functions from scipy.signal use
@@ -27,8 +27,20 @@ Author: Eric Kooistra, nov 2023
 
 [1] dsp_study_erko.txt, summary of DSP books
 [2] pyfda, dsp, at https://github.com/chipmuenk
-[3] Try FIR filter design methods
-    * dsp.py import for Python jupyter notebooks
-    * filter_design_firls.ipynb
-    * filter_design_remez.ipynb
-    * filter_design_windowed_sync.ipynb
+[3] dsp.py import for Python jupyter notebooks
+[4] python jupyter notebooks
+    * Try FIR filter design methods
+      - rectangular_window_and_ideal_lpf.ipynb
+      - filter_design_windowed_sync.ipynb
+      - filter_design_firls.ipynb
+      - filter_design_remez.ipynb
+    * Try Hilbert transform
+      - hilbert_transform_design.ipynb
+      - hilbert_transform_application.ipynb
+    * Try IIR filter design methods
+      - iir_filter.ipynb
+    * Try multirate processing
+      - up_down_sampling.ipynb
+      - narrowband_noise_generator.ipynb
+    * Try polyphase filterbanks
+      - one_pfb.ipynb