The Southampton Nostalgia Scale is available for download below as a PDF document.
Barrett, F. S., Grimm, K. J., Robins, R. W., Wildschut, T., Sedikides, C., & Janata, P. (2010). Music-evoked nostalgia: Affect, memory, and personality. Emotion, 10, 390-403.doi:10.1037/a0019006
PLEASE NOTE : The 7- item version is a new version which adds two new items to the original 5-item scale reported by Routledge et al. (2008). It was first reported by Barrett et al. (2010).
Routledge, C., Arndt, J., Sedikides, C., & Wildschut, T. (2008). A blast from the past: The terror management function of nostalgia. Journal of Experimental Social Psychology, 44, 132-140.