Sources

1) Source: The History of Parliament . External Link
http://www.historyofparliamentonline.org/volume/1386-1421/member/cumberworth-robert-14045. Reference: Cumberworth, Robert (d.1404/5), of Somerby and Stain, Lincs. (Questionable reliability of evidence)
2) Source: The History of Parliament . External Link
http://www.historyofparliamentonline.org/volume/1386-1421/member/constable-sir-robert-1353-1400. Reference: Constable, Sir Robert (c.1353-1400), of Flamborough, Yorks. (Questionable reliability of evidence)
3) Source: The visitation of Yorkshire in the years 1563 and 1564. Reference: 63-66: Constable of Flamborough (Questionable reliability of evidence)