All briefs must follow a standard structure called a style. This means that your brief must follow certain rules for formatting, grammar, punctuation, and citations. These rules are set out in a document called a style guide. The "Oregon Appellate Courts Style Manual" is the style guide for briefs submitted to the Oregon Appellate courts.
The Oregon Judicial Department's Publications website has PDF copies of the Oregon Appellate Courts Style Manual available for download:
The Oregon Rules of Appellate Procedure (ORAP) are the rules that apply to proceedings in the Oregon Court of Appeals and the Oregon Supreme Court.
It is important that you read the entire ORAP in preparation for your case. Browsing the table of contents is a good way to familiarize yourself with the structure of the rules. Rule 5 covers the preparation and filing of briefs. This rule is the source of many of the requirements detailed in the Style Manual linked above.
Listed below are some places you can view briefs submitted to Oregon appellate courts.
It is important to remember that there is no guarantee that these briefs are correctly written. You should evaluate any example you use in the light of the rules, reference works, and other briefs.
The Bluebook by 
The Chicago Manual of Style by 
Webster's Third New International Dictionary by 