diff --git a/esbo_etc/classes/optical_component/Filter.py b/esbo_etc/classes/optical_component/Filter.py
index c427ac3..a20fed7 100644
--- a/esbo_etc/classes/optical_component/Filter.py
+++ b/esbo_etc/classes/optical_component/Filter.py
@@ -11,6 +11,7 @@ class Filter(AHotOpticalComponent):
     A class to model a filter component and its thermal emission. The model can be created from a file, the name of
     a band or a custom spectral range.
     """
+    # Bands from Handbook of Space Astronomy and Astrophysics p. 139
     _band = dict(U=dict(cwl=365 * u.nm, bw=68 * u.nm), B=dict(cwl=440 * u.nm, bw=98 * u.nm),
                  V=dict(cwl=550 * u.nm, bw=89 * u.nm), R=dict(cwl=700 * u.nm, bw=220 * u.nm),
                  I=dict(cwl=900 * u.nm, bw=240 * u.nm), J=dict(cwl=1250 * u.nm, bw=300 * u.nm),
diff --git a/esbo_etc/classes/target/BlackBodyTarget.py b/esbo_etc/classes/target/BlackBodyTarget.py
index da79667..44be86d 100644
--- a/esbo_etc/classes/target/BlackBodyTarget.py
+++ b/esbo_etc/classes/target/BlackBodyTarget.py
@@ -9,7 +9,7 @@ class BlackBodyTarget(ATarget):
     """
     This class models the spectral flux density of a star of given magnitude using as black body radiator
     """
-    # Bands from Handbook of Space Astronomy and Astrophysics
+    # Bands from Handbook of Space Astronomy and Astrophysics p. 139
     _band = dict(U=dict(wl=365 * u.nm, sfd=4.27e-11 * u.W / (u.m ** 2 * u.nm)),
                  B=dict(wl=440 * u.nm, sfd=6.61e-11 * u.W / (u.m ** 2 * u.nm)),
                  V=dict(wl=550 * u.nm, sfd=3.64e-11 * u.W / (u.m ** 2 * u.nm)),