mono/netcore/System.Private.CoreLib/shared/System/Globalization/CalendarWeekRule.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

namespace System.Globalization
{
    public enum CalendarWeekRule
    {
        FirstDay = 0,           // Week 1 begins on the first day of the year

        FirstFullWeek = 1,      // Week 1 begins on first FirstDayOfWeek not before the first day of the year

        FirstFourDayWeek = 2    // Week 1 begins on first FirstDayOfWeek such that FirstDayOfWeek+3 is not before the first day of the year        
    };
}