Tetney Hoard:
John Walker’s account of the hoard of mid 10th C., two-line type pennies found near Tetney, Lincs., 1945. (Accessed via JSTOR. Free registration allows the user to read up to 6 documents a month):
https://www.jstor.org/stable/42663196?seq=1#metadata_info_tab_contents
Northampton Mint:
The second (the reigns of Cnut to Stephen) of William C. Wells’ four papers on the output of the Northampton and Southampton mints (relevant plates at the very end of the second link):
https://www.britnumsoc.org/publications/Digital%20BNJ/pdfs/1929_BNJ_20_8.pdf
https://www.britnumsoc.org/publications/Digital%20BNJ/pdfs/1927_BNJ_19_4.pdf