Rahn's book was published 1980

setclass/setclass.py

@@ -4,6 +4,7 @@ class cache_property:
     """
     Property that only computes its value once when first accessed, and caches the result.
     """
+
     def __init__(self, function):
         self.function = function
         self.name = function.__name__
@@ -17,6 +18,7 @@ class SetClass(list):
     """
     Musical set class, containing zero or more pitch classes.
     """
+
     def __init__(self, *args: int, tonality: int = 12):
         """
         Instantiate a Class Set with a series of integers. Each pitch class is "normalised" by
@@ -105,7 +107,7 @@ class SetClass(list):
         An ordered tuple containing the multiplicities of each interval class in the set class.
         Denoted in angle-brackets, e.g.
         The interval vector of {0,2,4,5,7,9,11} is ⟨2,5,4,3,6,1⟩
-        — Rahn (1987), p. 100
+        — Rahn (1980), p. 100
         """
         from itertools import combinations
         iv = [0 for i in range(1, int(self.tonality / 2) + 1)]
@@ -118,7 +120,7 @@ class SetClass(list):
         """
         The ordered interval or "directed interval" (Babbitt) of two pitch classes is determined by
         the difference of the pitch class values, modulo 12:
-        i⟨a,b⟩ = b-a mod 12  — Rahn (1987), p. 25
+        i⟨a,b⟩ = b-a mod 12  — Rahn (1980), p. 25
         """
         return (b % 12 - a % 12) % 12
 
@@ -127,7 +129,7 @@ class SetClass(list):
         The unordered interval (also "interval distance", "interval class", "ic", or "undirected
         interval") of two pitch classes is the smaller of the two possible ordered intervals
         (differences in pitch class value):
-        i(a,b) = min: i⟨a,b⟩, i⟨b,a⟩  — Rahn (1987), p. 28
+        i(a,b) = min: i⟨a,b⟩, i⟨b,a⟩  — Rahn (1980), p. 28
         """
         return min(SetClass.ordered_interval(a, b), SetClass.ordered_interval(b, a))
 
@@ -135,7 +137,7 @@ class SetClass(list):
     def versions(self):
         """
         Returns all possible zero-normalised versions (clock rotations) of this set class,
-        sorted by brightness. See Rahn (1987) Set types, Tₙ
+        sorted by brightness. See Rahn (1980) Set types, Tₙ
         """
         # The empty set class has one version, itself
         if not self.pitch_classes:
@@ -154,7 +156,7 @@ class SetClass(list):
         """
         Return the Rahn normal form of the set class; Leonard describes this as "most dispersed from
         the right". Find the smallest outside interval, and proceed inwards from the right until one
-        result remains. See Rahn (1987), p. 33
+        result remains. See Rahn (1980), p. 33
         """
         # Set class {0,2,4,5,8,9} has four darkest versions:
         # {0,2,4,5,8,9}   B = 28