To create a valid Dockerfile, the instructions must follow a specific logical order:

1. FROM: Every Dockerfile must start with a base image (e.g., python:3.6-alpine).
2. EXPOSE: Since the application is hosted as a web application accessible remotely, it needs to inform Docker that the container listens on port 8080 at runtime.
3. ENTRYPOINT & CMD: When used together in "exec form," ENTRYPOINT defines the main command (python3), while CMD acts as the default flags or arguments (-m, server). This allows the container to run as an executable. EXEC and PORT are not valid Dockerfile instructions.

Docker Documentation: Dockerfile reference - FROM. Defines the initial stage and sets the Base Image for subsequent instructions.

Docker Documentation: Dockerfile reference - EXPOSE. Explains how the instruction functions as documentation between the image developer and the person running the container regarding which ports are intended to be published.

Docker Documentation: Dockerfile reference - ENTRYPOINT vs CMD. Detailed breakdown of how ENTRYPOINT sets the executable and CMD provides default arguments that can be overridden.

Open Container Initiative (OCI): Runtime Specification. Standards regarding how container engines execute commands and handle entrypoints within isolated environments.