BabyCenter's "What's Your Discipline Style?" includes a downloadable chart of different discipline philosophies (Positive Discipline, Gentle Discipline, Boundary-Based Discipline, Emotion-Coaching, and Behavior-Modification) with a summary of each one's primary emphasis, techniques, and an example of how it works. At the end of each column are the names of 1-3 books on that particular school of thought so you can learn more.
Here's another article that may broaden your scope: "How They Do It: An Overview of Child Rearing around the World." It gives a brief overview of discipline beliefs and strategies in China, Japan, India, Egypt and Africa, as well as Native American, Latino and European cultures. Here are some excerpts.
Discipline practices in China are based on ancient Confucian ethics
and the belief that infants arrive from the gods with an inherently
good nature that is to be respected.
Indian moms lovingly massage their babies daily and carry them close
to their bodies. Co-sleeping during the early years is another
characteristic of the close mother-infant relationship.... [However],
discipline is often strict and children are taught to obey their
In [Mali, Nigeria, Namibia, Zambia, and Malawi], not only are children
highly valued, but being childless is considered the worst fate that
can befall a man and a woman. The entire community considers it their
responsibility to see that each child, a “gift of God,” is raised
appropriately. Elders transmit their cultural values and teach the
young, and discipline centers around the values that children are
expected to learn.