Two ways are highly recommended in general. For one thing, ordinary people today could make full use of modern technology, like the Internet for example. Thanks to the Internet and its related products, in recent years, we have more choices or possibilities to have a better understanding of all kinds of information. Ranging from education to work, from everyday life to history. More importantly, the public resources could be nearly free of charge as well. Imagine that typing something you are looking for in the laptop, then desired results would be on. A quite efficient way I suppose. For another, I personally recommend the city library or related departments. Since millions of important papers can be found in those area. When we want to find out the truth, such kinds of places can be identified. However, the problem is that we need to make reservations in 7 days at least, meanwhile, we have to pay for this as well. So, here are two ways that I recommend. That is it.