After reading some works, mainly by Kosgaard, I was wondering if there were any other in-depth contemporary literature looking into Kantian ethics and, more precisely, into its problems (and their potential solutions), mainly those concerning the formulation of the categorical imperative, the proper formulation of maxims, and of the possibility of false positives or false negatives.
Also, I'd like to know, if possible, if there are authors, who although not Kantian themselves, develop ideas close to Kantian deontology, or close to deontology in general.
Thanks.