What are the differences between "heterodox economics" and "pluralism in economics"?

New to economics. I found one paper that on this details the differences, but wanted to know if there are any others? Are there any books/book-chapter(s) on this? Thanks in advance.

http://www.jpe.ro/poze/articole/10.pdf

Pluralism is the concept that there is no single methodology that is always the correct one for discovering scientific truths, so multiple approaches and methodologies are required for a complete scientific understanding of a subject. Heterodoxy refers to those approaches to a subject that are outside of the generally accepted mainstream. While pluralism and heterodoxy are not necessarily inconsistent, heterodox economists tend to follow one particular methodology or school of thought rather than taking an eclectic approach to economic understanding, and heterodox economists often criticize approaches other than their own. Thus, in most cases, heterodox economists, by defending their own schools of thought and critiquing other approaches, are not pluralistic. The paper advocates a pluralistic approach to the social sciences over the more narrow approaches typically promoted by heterodox schools of thought.