I have never heard of go-to-magazine/monkey. However, there are terms 'go-to-guy' or 'go-to-girl'. A 'go-to-' person is a person that is capable of dealing with difficult problems and solving them. He/she is the person you would 'go to' if you had some problem. It usually has to do with some area. 'Joan is our go-to-girl for shipping problems. She has the most experience." "Tom is our go-to-guy for overseas sales."

Here is a good example. If you love to surf, and you want the newest information on surfing then your "go to magazine" would be Surf Magazine. If you love gossip, then your "go to magazine" would be a tabloid. "Go to~" means exactly what it says, it is the thing you would use to get whatever information you want. If you wanted to know about fixing cars, your "go to person" would be a mechanic, etc.