"Kept it upon the plates of Nephi"

1. 4 Ne. 1: 19, 21
     19 And it came to pass that Nephi, he that kept this last record, (and he kept it upon the plates of Nephi) died, and his son Amos kept it in his stead; and he kept it upon the plates of Nephi also.
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     21 And it came to pass that Amos died also, (and it was an hundred and ninety and four years from the coming of Christ) and his son Amos kept the record in his stead; and he also kept it upon the plates of Nephi; and it was also written in the book of Nephi, which is this book.