I'd strongly recommend getting the hang of at least one bibliographic software package (e.g. Reference Manager, Endnote, Mendeley, Zotero). Not only will it make it massively easier to insert citations/footnotes into your work, most have additional functions like pdf annotation or the ability to tag/file your papers into collections.
I use Mendeley and find it pretty good, but I've also used Endnote and Reference Manager in the past for inserting citations. They all have their flaws, but it's worth using one anyway.
It might also solve your cross-computer issues - Mendeley desktop can be synced across devices.