Software Complexity Metrics by Halstead, 1977.
Program Vocabulary, Implementation Length, Length Equation, Program Volume, Time Equation, Program Difficulty, Program Effort, Program Level, Intelligence Content
Software Complexity Metrics by McCabe, 1989.
Cyclomatic Complexity, Decision Density
Maintainability Index, Welker, 1995.
Object-Oriented Design Quality Metrics - Analysis of Dependencies by Martin, 1994.
Afferent Couplings, Efferent Couplings, Abstractness, Instability, Distance from the Main Sequence. Normalized Distance
OO Metrics by Chidamber and Kemerer, 1994.
Weighted Methods Per Class, Depth of Inheritance Tree, Number of Children, Coupling between Object, Classes, Response for a Class, Lack of Cohesion in Methods, LCOM5 (Henderson-Sellers, 1996), Coh (Briand, 1998)