The principal source used for the first known date of a settlement was:

Smith, A.H., The place-names of the West Riding of Yorkshire, Part 3: Morley wapentake, English Place-Name Society Vol. 32, (Cambridge, Cambridge University Press, 1961).

The documents cited by Smith as his source are given in the Source Document section for each record. It should be noted that these are not always entirely clear. Smith was supplemented by a card index compiled by Stephen Moorhouse for the following work:
Faull, M. L. and Moorhouse, S. A. (eds.), West Yorkshire: an archaeological survey to A.D. 1500, (Wakefield, West Yorkshire Metropolitan County Council, 1981). See pp.585-613 and map 25 in particular.
This card index is held at the West Yorkshire Archaeology Advisory Service. Historic Environment Record

A complementary settlement dating source was provided by the physical evidence of buildings with dates inscribed on them. A geocoded database of these has been created by David Cant of the Yorkshire Vernacular Buildings Study Group who kindly provided it as source material. These dates have the source given as ‘Dated building’

The issues involved in using these sources are discussed in:
Smith, N., Settlement and field patterns in the South Pennines: a critique of morphological approaches to landscape history in upland environments, unpublished PhD thesis, Lancaster University, 2013. See pp.130-136 and Appendix 3.

The additional information for settlements in Stansfield township is derived from the local valuation of 1805 held at:
West Yorkshire Archive Service (Calderdale) SU 405