Add a few introductory references
Merge branch 'master' of https://github.com/anu-atom-optics/larger-number-squeezing-paper.git
Merge branch 'master' of https://github.com/anu-atom-optics/larger-number-squeezing-paper.git
Merge branch 'master' of https://github.com/anu-atom-optics/larger-number-squeezing-paper.git
Add references plus minor tweaks