How should a series of articles be represented on my CV?
The way you do it is just fine. It allows the interested reader of your CV to find the articles in question and peruse them, which is exactly what you want to achieve. 

(As a side note, it is not uncommon for people to publish sequences of articles that start out the same, then have a roman numeral, and then some further text. For example numbers 34 and 47 on my list of publications are of this form: http://www.math.colostate.edu/~bangerth/publications.html#x-reviewed . Here is a much longer sequence by one of my teachers: https://scholar.google.com/scholar?hl=en&amp;as_sdt=0%2C6&amp;q=heywood+rannacher&amp;btnG= .)