1. ‘Pantograph and overhead-line dynamics’, Report EL, 69, British Railways Research Department, 1967 Chap. 1
2. Muddle, R.P.: ‘Digital-computer program for a model of a railway overhead-contact system’, RAE Farnborough Technical Mathematical Memorandum 71, 1966)
3. ‘The numerical solution of a fourth order partial differential equation pertaining to railway overhead-contact systems’, RAE Farnborough Technical Report, 67299, 1967 Section 4.1