It looks like they are the sons of Homer/Horace Clough and Ada May True.
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Homer is the son of Amos Clough and Susan Dudley. Ada may be the dau. of George True.
U S Census, 1920 Haverhill, Grafton, NH
Citing this Record: "United States Census, 1920," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MH86-1PF
Head Horace B Clough M 36 VT (Homer/Honor on other records)
Wife Ada M Clough F 33 NH
Dau Katucka B Clough F 15 NH
Son Llewellyn S Clough M 13 NH
Son Clough M 11 NH
Son August E Clough M 7 NH
Dau Vera M Clough F 5 NH
Son Arlo E Clough M 3 NH
Son Glen B Clough M 1 NH
U S Census, 1910 Norwich, Windsor, VT
Citing this Record: "United States Census, 1910," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MPFN-VLG
Head Susie Pennoch F 47 NH
Son Grover R Pennoch M 17 VT
Dau-in-law Ada Clough F 22 NH
Grandson Lewellyn W Clough M 3 NH
Grandson Theodore J Clough M 1 NH
New Hampshire, Marriage Records, 1637-1947
Citing this Record: "New Hampshire, Marriage Records, 1637-1947," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/FLXD-M5M
Name: Carlos P. Pennock
Age: 67 Norwich, Windsor, VT Birth (Est):1824
Second Marriage
Father Barzelia Mother Mary A. Johnson
Marriage 24 Feb 1891 Hanover, Grafton, NH
Spouse: Susie Clough
Age: 33 Birthplace: Hanover, Grafton, NH Birth (Est): 1858
Second Marriage
Father George T. Dudley Birth Hanover, NH
Mother Mary Carpenter Birth Hanover, NH
New Hampshire, Deaths and Burials, 1784-1949
Citing this Record: "New Hampshire, Deaths and Burials, 1784-1949," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/FDKF-PF8
Name: Homer B Clough
Death 28 Jun 1947 Concord, Merrimack, NH
Spouse Ada May True
Father: Amos Clough Mother Suzy Dudley
This page has the marriages of many children of Homer Clough and Ada M True, siblings of Llewellyn.
https://familysearch.org/search/record/results?count=20&query=%2Bsurname%3Aclough~%20%2Bbirth_place%3Anh~%20%2Bbirth_year%3A1890-1910~%20%2Bfather_givenname%3A%22homer%20horace%22~%20%2Bfather_surname%3Aclough~%20%2Bmother_givenname%3Aada~