1. Checklist of United States public documents 1789-1909, congressional on the US Government Sources page; Contains lists of congressional and departmental publications.
2. Massachusetts State Documents Online on the Massachusetts Information page; Includes recent documents that are published solely in electronic form and heavily-used series that have been digitized, such as Massachusetts Election Statistics and the Massachusetts Acts and Resolves.
3. The Complete Work of Charles Darwin Online on the Science Sources page; Includes Darwin's published writings and unpublished papers.
4. Correspondence of Charles Darwin on the Science Sources page; Contains around 14500 entries which summarise the contents of all the known surviving letters written both by and to Charles Darwin.
