C. F. Keil and Franz Delitzsch on 1 Chronicles 7:1-5

1Ch 7:1-5 Sons and families of Issachar. - 1Ch 7:1. Instead of ולבני, we must certainly read בּני, as in 1Ch 7:14, 1Ch 7:30, or וּבני, as in 1Ch 7:20; 1Ch 5:11, and elsewhere. The לבני has come into the text only by the recollection of the copyist having dwelt on the so frequently recurring לבני in 1Ch 6:42, 1Ch 6:46-47, cf. 1Ch 6:48, 1Ch 6:56, 1Ch 6:62, for it is not possible to take ל as the ל of introduction, because the names of the sons follow immediately. The names of the four sons are given as in Num 26:23., while in Gen 46:13 the second is written פּוּה, and the third יוב;vide on Gen. loc. cit.