If you use the `sources` parameter, you can choose which of these data sources to include in your search. So if you're only interested in finding a YMCA in data from OpenAddresses, for example, you can build a query specifying that data source.
The [Who's on First](https://whosonfirst.org/) gazetteer is one of the datasets used as a source of search data. Use this table is a reference between the parameters for structured geocoding and the [types of places in Who's on First](https://whosonfirst.mapzen.com/placetypes/).
The [Who's on First](https://whosonfirst.org/) gazetteer is one of the datasets used as a source of search data. Use this table is a reference between the parameters for structured geocoding and the [types of places in Who's on First](https://whosonfirst.org/placetypes/).
| Structured geocoding parameter | Who's on First placetype |