It is this Sothic period which Manetho has employed in his account of Egyptian history.
"History Of Egypt From 330 B.C. To The Present Time, Volume 10 (of 12)" by S. Rappoport
Another Sothic date of the 7th year of Senwosri III.
"Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 1" by Various