There are several types of periodicals that you may wish to use, depending on your research needs.

Scholarly Journals

• Content: In-depth research or original findings by researchers.
• Author: Specialist or scholar in the field.
• Audience: Scholars, students, other researchers.
• Layout: Few advertisements and photos, many charts and tables.
• Language: Specialized terminology that often requires expertise.
• Objectivity: Peer-Reviewed (evaluated by other experts).
• References: Usually required. Facts and quotes are verifiable.
• Examples: Journal of Abnormal Psychology, Italian Journal of Pediatrics.

Popular Magazines

• Content: General information to entertain and inform.
• Author: Journalist who may or may not be an expert in the field.
• Audience: General public.
• Layout: Glossy advertisements and photos, few graphs and charts.
• Language: General-use vocabulary.
• Objectivity: Content evaluated by editorial staff, not experts.
• References: Rare.
• Examples: National Geographic, Time, Newsweek.

Trade Magazines

• Content: Practical information for professionals working in the field.
• Author: Professional in the field or journalist with subject expertise.
• Audience: Professional in the field.
• Layout: Some professional ads and photos, newsletter format.
• Language: Specialized terminology, but not as technical as scholarly journals.
• Objectivity: Content evaluated by editorial staff, not experts.
• References: Occasional brief bibliographies, but not required.
• Examples: PC World, Psychology Today, Architectural Record.

These examples based on the following article:

If an article is "peer-reviewed," this means that it has been sent to other experts in the field, who have evaluated the article and deem it accurate enough to be published. While this process eliminates most papers that have glaring errors, it is not entirely free from bias.