A Step-by-Step Guide to Systematically Identify all Relevant Animal Studies. Review article in Laboratory Animals, 46:(24-31), 2012. (PDF)

Animal Welfare Information Center (AWIC) - USDA

European Union Reference Laboratory for alternatives to animal testing (EURL ECVAM)

Fund for the Replacement of Animals in Medical Experiments (FRAME) - Organization in the UK promoting the Three R's in research and testing

Guide to Literature Searches for Animal Testing Alternatives- from the University of Texas San Antonio Library

Humane Endpoints in Laboratory Animal Experimentation - Hosted by Utrecht University Department of Animals in Science and Society

Model Organisms for Biomedical Research - Mammalian and non-mammalian models, National Institutes of Health

National Centre for Replacement, Refinement and Reduction of Animals in Research (NC3Rs) - UK organization dedicated to the 3Rs; collaborate with scientists and organisations from across the life sciences sector; fund research and early career development; support open innovation and the commercialization of 3Rs technologies; and stimulate changes in policy, regulations, and practice.

National Toxicology Program, Interagency Center for the Evaluation of Alternative Toxicological Methods - (NICEATM) activities support the development and evaluation of new, revised, and alternative methods to identify potential hazards to human health and the environment, with a focus on replacing, reducing, or refining animal use.

Netherlands Centre Alternatives to Animal Use - promotes application of 3R-alternatives in the Netherlands 

Novartis infographic -- Why Animal Research?

Tracking System for Alternative test methods Review (TSAR) - Validation and Approval in the Context of EU Regulations on Chemicals

Veterinary Educational Tools - from Colorado State University, free access to detailed anatomical dissections online