public class RecordItem
		{
			public int Year { get; set; }
			public List<int> Monthes { get; set; }
		}

		public class Record
		{

			public IList<RecordItem> recordItems { get; private set; }
			public Record(IEnumerable<RecordItem> items)
			{
				recordItems = items.ToList();
			}
			public static IEnumerable<RecordItem> getAggregatedRecords(IEnumerable<Record> records)
			{
				var q =
					from g in (
						from i in (from r in records
						from i in r.recordItems
						select i)
					group i by i.Year
					)
					select new RecordItem(){
						Year = g.Key,
						Monthes = (
								from items in g
								from m in items.Monthes
								select m)
							.Distinct()
							.ToList()
					};
				return q;

			}
			public Record(IEnumerable<Record> records)
			{
				recordItems = getAggregatedRecords(records).ToList();
			}
		}

		[TestMethod]
		public void TestMethod1()
		{
			var records = new Record(
				new [] {
					new Record(new List<RecordItem>{
						new RecordItem{ Year = 2008, Monthes = new List<int>{1,2} },
						new RecordItem{ Year = 2009, Monthes = new List<int>{6,7} }
					}),
 
					new Record(new List<RecordItem> {
						new RecordItem{ Year = 2009, Monthes = new List<int>{7,8}},
						new RecordItem{ Year = 2010, Monthes = new List<int>{1,3,4}}
					})
				});
		}