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));
	}
}

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