Русско-англо-русский юридический словарь

Employers are obliged to keep records of working time for each employee. (Rights at work by John Halson)

They also are required to put in place a system to monitor the number of hours worked and keep records of working time as required by the new regulations. (heraldscotland.com)

Supplemental agreements are legally binding documents that are used to modify contracts that are already in force. This type of document is sometimes used as a means of allowing the existing agreement to remain in place with the same ending date, while adding or removing some provisions or terms to the working relationship. A supplemental agreement is often an ideal solution when there is no desire to renegotiate an entirely new contract to take the place of the current agreement. (WiseGEEK)

Working time is the period of time that an individual spends at paid occupational labor. Unpaid labors such as personal housework or caring for children/pets are not considered part of the working week (Wikipedia)