using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
    	var text = "Artículo 1. This is a test that includes : 1) Sample text 2) Sample text";
    	var result = Regex.Split(text, @"(?!^)\s+(?=\bArtículo\s+[0-9]+\.|[a-z]\)|[1-9]\d?\)|\bPárrafo\b)", RegexOptions.None);
    	Console.WriteLine(string.Join("\n", result));
	}
}