/// <summary>Constructor</summary>
/// <param name="name">Name</param>
/// <param name="symbol">Symbol</param>
/// <param name="amount">Amount of reference units (1 for the base unit)</param>
/// <param name="reference">Reference Measure Unit (null for the base unit)</param>
/// <exception cref="ArgumentException">Amount must be positive</exception>
/// <exception cref="TypeInitializationException">Created unit and the reference unit must belong to the same measure equivalence class</exception>
/// <exception cref="TypeInitializationException">First unit of the equivalence class must have rate equal to 1</exception>
public WeightUnit(string name, string symbol, decimal amount = 1, WeightUnit reference = null) :
base(name, symbol, amount, reference)
{
}
static WeightUnit()
{
Kilogram = new WeightUnit("kilogram", "kg");
}