He edited James Scott Skinner's biggest collection of music, The Harp & Claymore Collection, providing harmonies for Skinner's compositions, and he was jointly responsible for compiling The Greig-Duncan Folk Song Collection, with the Rev J. B. Duncan (1848–1917). A selection from this collection of over 3000 songs and tunes was published in 1925. Two volumes were published in 1981-1982, but the full collection, in eight volumes, was only finally published between 1981 and 2002.
- Short biography. Accessed 11 October 2007
- Ballantyne, Pat The Harp & Claymore Collection. Accessed 26 January 2009
- How I wish Gavin Greig to clothe that... Accessed 14 January 2009
- Note from Skinner to Greig re The Valley of Silence. Accessed 14 January 2009
- Purser, John The Greig-Duncan Folk Song Collection, Musical Traditions, 20 December 2002. Accessed 11 October 2007
- Olson, Ian A. The Greig-Duncan Folk Song Collection, Musical Traditions, 5 February 2003. Accessed 26 January 2011
- Barron, Charles Doric Drama Archived 10 June 2007 at the Wayback Machine, The Elphinstone Kist. Accessed 11 October 2007