URLDate
Verified		Extra Software
Requirements
(if any)		Access
Conditions		Notes
https://d.lib.msu.edu/gress/65/OBJ/view#page=807/10/2017PDF ReaderItem is within a single large file
https://listings.lib.msu.edu/gress/2012vol4.pdf#page=84/18/2017PDF ReaderItem is within in a single large file
http://www.nga.no/assets/files/gressforum/gressfor[...]08/29/2018PDF ReaderItem is within a single large file; Variant pictures; Gressforum reprint