The Business Expert Press collection of ebooks has LOTS of books on all aspects of "Marketing" and writing marketing plans. Here are a few examples, and then a link that will bring up the whole list (and get you into the Business Expert Press database, so you can do more searching on your own). All practical and real-world, and all fully downloadable to your own device!
A couple of books on this specific topic, then a link that will generate a list of additional titles:
For more on the 4p's and other aspects of the theory of marketing, or the use of marketing by a particular company or for a particular product, article and news databases are an excellent resource. Factiva and LexisNexis Academic are news databases, ABI/INFORM, Business Source Premier, and ScienceDirect are article databases (they are arranged by the percentage of scholarly journals they cover - less in ABI, most in ScienceDirect).
If you need to do market or industry research... These first 3 databases are our best "all-around," full-spectrum-of-industries resources:
Try the following databases if your research is more consumer or "daily life products"-oriented:
The following databases are our best resources for hi-tech or medical/pharma market research: