2. Evaluation of National Concessionary Travel Scheme, Scottish Government Social Research, Halcrow Group Ltd, 2009
3. Improving the evidence for setting the reimbursement rate for operators under the Scotland-wide older and disabled persons concessionary bus scheme, 2010, Institute for Transport Studies, University of Leeds.
4. The local authority areas were: Aberdeen, Dundee, Edinburgh, Glasgow, Inverclyde, North Lanarkshire, and Stirling.