These policies and strategies should be developed from, and supported by, information from a range of sources including, where available:
Dylai’r polisïau a’r strategaethau hyn gael eu datblygu ar sail gwybodaeth o ystod o ffynonellau, ynghyd â chael eu hategu gan wybodaeth o’r fath, yn cynnwys y canlynol pan fyddant ar gael: