      - parameter to: `destination unit`.
      
      - returns: `amount` converted from a `source unit` to a `destination unit`.
+     
+     - author: Michal Konturek
      */
     public func convert(amount: NSNumber, from: Unit, to: Unit) -> NSNumber {
         let baseAmount = from.convertToBaseUnit(amount)

     - parameter amount: `amount` in the `current unit`.
     
     - returns: `amount` converted to a `base unit`.
     */
    public func convertToBaseUnit(amount: NSNumber) -> NSNumber {
        let converted = NSDecimalNumber(decimal: amount.decimalValue)

     - parameter name: unit name.
     - parameter symbol: unit symbol.
     - parameter ratio: conversion ratio to a base unit.
     
     - author: Michal Konturek
     */
    public init(name: String, symbol: String, ratio: NSNumber) {
        self.name = name
