Stanley Coren ranked dog breeds by intelligence in his book The Intelligence of Dogs based on surveys done on dog trainers, the article for which contains a summary of the rankings obtained. (sheppardsoftware.com)
Classic Rottweilers have been using in military and police, which indicates the level of intelligence of these dogs. (petful101.com)
In this study, the group partnered with József Topál, a Hungarian pioneer of canine research who specialises in dog - human interaction and the social intelligence of dogs. (sciencedaily.com)