There are few works that deal with this issue specifically but plenty of work where this is covered in various contexts. Helot-homoioi relations mostly concern three areas: structure of Spartan economy where helots worked the land and homoioi fought, the sheer size of helot population and constant threat of rebellion and means to prevent that (these two issue are connected) and later lack of manpower and need to include other classes in phalanx. So authors who talk about economy can't ignore the helots, authors who talk about foreign policy can't ignore them either, later wars to end Spartan hegemony understood that freeing helots was crucial in tanking Spartan economy etc. So you might root around works that cover these aspects to find something of the topic (works about their economy often offer good insights).

Overall I'd start with Paul Cartledge who wrote extensively about Sparta, covering various aspects. For example Spartan Reflections, 2001, has chapter "Rebels and Sambas in Classical Greece: A comparative View" which deals with slavery in Greece so of course helots can't be ignored. It's interesting work as it contrasts various approaches to slavery in Greece. Of course with author who published so many work and aims some of it to general public you'll see certain ideas, points and angles recycled in different works.

Then there is Sparta, Michael Whitby (ed), 2002, which is a collection of essays, lectures and such. For you relevant chapter would be Perioeci and Helots, one deals with Perioeci but The Helot Threat, (G. E. M. de Ste Croix, taken from his The Origins of the Peloponnesian War, 1972) and The Obligation of Helots (Jean Ducat, translation of his 1990 French article) deal with Helots and titles are pretty self explanatory. Both books also cover later Spartan decline and that includes various ways to get military service out of helots, but as I've said in the beginning, you'll have to dig relevant parts out of wider work.

And even if these two books are not (exactly) what you are looking for they are certainly a good start and bibliographies will point you in right direction.