I would think the following book would also apply to security in refactoring:

Winkler, V. J. (2011). Securing the Cloud: Cloud computer Security techniques and tactics. Elsevier.

You can enrich your understanding in cloud refactoring:

http://people.cs.vt.edu/tilevich/papers/asej.pdf

New research finds that, contrary to popular belief, restructuring software code to be more maintainable and efficient may not be worth the time and effort.

Refactoring software, that is, restructuring existing source code to make it more readable, efficient, and maintainable, is something all developers do every now and again.

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