1a.  LDS.  Family Search: Internet Genealogy Service:  IGI - International Genealogical Index (online at FamilySearch.org).

Seth HARRINGTON Birth: 05 Jun 1728, Watertown, Middlesex, Massachusetts Father: George HARRINGTON; Mother: Hephzeba Source: LDS Film/Fiche #0874146: Watertown Records. Historical Society of Watertown (Massachusetts)

Seth HARRINGTON Spouse: Priscilla HOUGHTON Marriage: 13 Nov 1760, Westminster, Worcester, Massachusetts Source: LDS Film/Fiche #0873751 - Item 5: Vital Records of Westminster, Massachusetts, to the end of the year 1849

Seth HARRINGTON Spouse: Rebeckah TEMPLE Marriage: 22 Jul 1814, Westminster, Worcester, Massachusetts Source: LDS Film/Fiche #0873751 - Item 5: Vital Records of Westminster, Massachusetts, to the end of the year 1849

Sarah HARRINGTON Birth: 10 Nov 1752, Westminster, Worcester, Massachusetts Father: Seth HARRINGTON; Mother: Abigail or Percilla Source: LDS Film/Fiche #0873751 - Item 5: Vital Records of Westminster, Massachusetts, to the end of the year 1849

Elisha HARRINGTON Birth: 31 Aug 1754, Westminster, Worcester, Massachusetts Father: Seth HARRINGTON; Mother: Abigail or Percilla Source: LDS Film/Fiche #0873751 - Item 5: Vital Records of Westminster, Massachusetts, to the end of the year 1849

Seth HARRINGTON Birth: 05 Jun 1756, Westminster, Worcester, Massachusetts Father: Seth HARRINGTON; Mother: Abigail or Percilla Source: LDS Film/Fiche #0873751 - Item 5: Vital Records of Westminster, Massachusetts, to the end of the year 1849

Daniel HARRINGTON Birth: 24 Feb 1758, Westminster, Worcester, Massachusetts Father: Seth HARRINGTON; Mother: Abigail Source: LDS Film/Fiche #0873751 - Item 5: Vital Records of Westminster, Massachusetts, to the end of the year 1849

Another source (patron submissions) assert that the mother of Sarah, Elisha, Seth, and Daniel is Abigail CHILD.

1b.  Franklin P. Rice.  1908.  Vital Records of Westminster, Massachusetts.  Boston, MA, p. 149.  Publication of Intention to marry to Rebecca TEMPLE, 22 Jul 1814.

1c.  LDS.  Family Search: Internet Genealogy Service:  AF - Ancestral File (online at FamilySearch.org).

Spouse: Abigail CHIDD Birth: 1734 Death: 21 Sep 1759, Westminister (sic), Worcester, Ma Marriage: Abt 1750

Spouse: Priscilla WILDER Birth: Abt 1738 Death: 28 Jan 1814, Westminister (sic), Worcester, Ma Marriage: 13 Nov 1750, Watertown, Middlesex, Ma

2.  William Sweetzer Heywood.  1893.  History of Westminster, Massachusetts... Vox Poluli Press, S.W. Huse & Co., Lowell, MA (online at HeritageQuest at Genealogy.com).  For a longer excerpt from the historical section of the book, see this page. 

p. 684

HARRINGTON. The earliest records of this name in New England have it Errington and Arrington.  The first of these forms soon received its aspirated prefix, making it Herrington, and this was the prevailing orthography for more than a century.  Robert Errington1, the immigrant, was one of the proprietors of Watertown in 1642.  He m. in 1649, Susannah George and had a son Thomas2, whose w., Rebecca Bemis, bore him George3, b. Aug. 1, 1695.  The latter m. Hepzibah, dau. of John and Abigail Fiske, whose sister was mother of John and Thomas Stearns of Nar. No. 2, and whose nieces were the wives of Samuel Hager and Stephen Sawin.  A cousin of Hepzibah m. Eliezer Bigelow.  So it appears that four of the oldest families in town were connected with each other by ties of blood relationship. 1. HERRINGTON, SETH4, was the 10th child of George and Hepzibah, b. Watertown, Sept. 15, 1729.  He is understood (italics mine) to have m. Sarah, dau. of Joshua and Grace (Bemis) Child, of whom mention has been made, coming here ab. 1750, possibly bef. m. took place.  They located on lot No. 23, now in possession of Ephraim Lufkin, which had been improved and built upon previously by Mrs. H.'s f.  She d. Sept. 30, 1759, leaving 4 chn., and he m. (2) Priscilla (Wilder), wid. of Benjamin Houghton of Lanc.  She had a dau., Priscilla Houghton, who d. Aug. 4, 1764, a. 5 yrs.  Seth Herrington d. Nov. 25, 1815, a. 86.  His w. d. the previous year, Jan. 28, 1814, a. 85.  He was afterward pub. to wid. Rebecca Temple, and prob. m. her a few months bef. his decease.  Chn.: [with Sarah CHILD] 2.  SARAH5, b. Nov. 10, 1752; m. Silas Holt; 2 chn. b. W. 3.  ELISHA5, b. Aug. 31, 1754; d. unm. Feb. 29, 1884. 4.  SETH5, b. June 5, 1756; prob. d. young. 5.  DANIEL5, b. Feb. 24, 1758; prob. d. young. [with Priscilla WILDER] 6.  ABIGAIL5, b. Dec. 23, 1763; m. (1) James Bowers and (2) Capt. Samuel Sawin; 2 chn.; res. W. 7.  EUNICE5, b. Aug. 31 1766; m. (1) Isaac Dupee and (2) Stephen Hunting; 2 chn.; res. W. 8.  BENJAMIN5, b. Jan. 7, 1769; m. Sarah Woodward; res. W. 9.  HANNAH5, b. Oct. 28, 1770; prob. d. young. [Continues the descent, but from Benjamin5 only.]

3.  Fredrick Lewis Weis.  1958.  Early Generations of the Family of Robert Harrington of Watertown, Massachusetts, 1634, and Some of his Descendants.  Self-published, Worcester, MA (online at HeritageQuest at Genealogy.com).