The main reference for this page is the movie itself.

The time series eventually became the main reference on global atmospheric change.

Here are the terms used in some of the main references.

This standard is the main reference used by archaeologists to reconstruct the system.

This is the main mathematical reference for the article.

In this section, each stage is given a name and a main reference.

Pictures exists on a Danish site, which also is main reference for this article.

The main reference for this article is a report from 1997:

The school uses textbooks and main references from respectable world publishers.

This is the main reference for the technical details of the article.