Comparative constitutional law is a wide-ranging and interdisciplinary topic.
The following publications are a particularly relevant sample that may be found in either the Kresge Law Library or Hesburgh Libraries. Some are available electronically.
The Kresge Law Library catalog may be searched here: EBSCO Discovery Service.
The Hesburgh Libraries catalog may be searched here: https:/library.nd.edu.
You might start with a Subject or general keyword search approach using "Comparative Constitutional Law". Customizing with additional terms like “constitutional interpretation”, “separation of powers” (both vertical and horizontal), “religion”, or “social rights” may help yield more targeted results.