The source in question is from the Minnesota Historical Society, and is composed of four PDFs in regards to targets by the Democratic National Committee focused on a series of Congressional Districts, Senate seats, and Governor seats up for election in 1978. This can likely be useful for timelines starting between 1976-1978 dedicated towards the impacts that might happen on the midterms. Because of the way the structure is set up, a total of four PDFs are provided with the info on the states respectively for it:
(Alabama-Indiana):
http://www2.mnhs.org/library/findaids/00697/pdfa/00697-00059-1.pdf
(Indiana-Nevada):
http://www2.mnhs.org/library/findaids/00697/pdfa/00697-00059-2.pdf
(Nevada-South Dakota)
http://www2.mnhs.org/library/findaids/00697/pdfa/00697-00059-3.pdf
(South Dakota-Wyoming)
http://www2.mnhs.org/library/findaids/00697/pdfa/00697-00059-4.pdf