Book of Mormon source analysis: Verse 16 gives us the hint of where Nephi receives this information. Nephi indicates that he does not make a "full account of the things which my father hath written". Lehi wrote his experiences, and Nephi is citing that written document here. It is interesting to note that while Nephi is clearly consulting a written source for his information, and gives some direct quotations (verse 14 should be a direct quotation from the Lehi source material), Nephi is nevertheless abbreviating the text. Nephi's introduction to his writings must cite Lehi for context and for the very *raison d'etre* of Nephi's record - but they are not the focus of Nephi's record. Nephi clearly expects that his father's record will stand on its own. Nephi may use it as a source, but he does not quote it extensively, preferring to develop a narrative for his own purposes.
For another discussion of Nephi's use of Lehi's material, see S. Kent Brown "Nephi's Use of Lehi's Record" in Rediscovering the Book of Mormon, ed. John L. Sorenson and Melvin J. Thorne. Deseret Book Company 1991: 3-14. Brown provides an interesting discussion of the probably material on which Lehi's record was made, and concludes that it likely was not metal, and therefore more likely to have been perishable (p. 5).