Citation systems

APA Citation System from Purdue's Online Writing Lab
MLA Citation System from Purdue's Online Writing Lab

WWU's Citation Resources
WWU's APA Guide
WWU's MLA Guide

Research and Citation Resources from Purdue's Online Writing Lab
Citing Sources from Duke University

ASA Style American Sociological Association from Cal State
Citing Sources in different disciplines

Research

Internet Search and Encyclopedia from Britannica
Library of Congress
University of Washington's Digital Collections online multimedia collections, especially strong in local history
Modern Language Association
American Psychological Association
Online Medical Library from the National Library of Medicine (NLM)