Q:

Alternatives to "then", "next" (at the beginning of the phrase) in formal text (for Academic papers)

I am writing an academic paper and, at a certain point, I want to write: "Firstly,... Then, ... Next, ... Lastly...."
However, "Then" and "Next" at the beginning of phrases sound like very INFORMAL English. I need FORMAL alternatives. What do you suggest/use?
I know this article suggesting "First... Second... Third... Lastly...":
First, Second, Third, and Finally
But I already used this structure somewhere else in the text, so I want to avoid repetition.
Thank you.

A:

Then: subsequently, in addition
Next: consequently
Finally: to conclude, to summarize
If your sentences and paragraphs are written in active voice, and they are tightly constructed, your reader will follow your sequence easily, without need for the linking words you asked about.

