The National Coal Resources Data System is an online database of analytical data, sample locations, descriptive information, analytical methods, sampling techniques, and bibliographic references for selected US coal samples provided by the USGS. Users are guided through several steps that include choosing the type of report to be generated, specifying sample search criteria, and whether to display or download the report. This can be one or a combination of items such as location, collector, rank, formation, bed, oxide ratio, and others. Once generated, each report contains all available data on the specific samples, which basically includes all information that can be included in searches. Even though similar report generating systems are often not user friendly, this site seems to be fairly straightforward and glitch-free.