1. Search engine: Use search engines such as Google, Bing, etc. to search for information related to "wholesale sources". The search results will show a large number of suppliers and product lists.

2. Social media: You can use social media such as Twitter, Facebook, etc. to seek recommendations for sources of goods in various industries, or join relevant industry groups and view the posts there.

3. Local Chamber of Commerce: Visit the local Chamber of Commerce and contact local wholesalers to obtain reliable source information.

4. E-commerce websites: Search online e-commerce websites such as Alibaba, eBay, etc. to find wholesale sources worldwide.