Mari Johannesdatter from Fet / Rælingen

One of the last branches to fill in with regards to the Norwegian part of my family tree is the ancestry of one Mari Johannesdatter from Fet, Akershus. I have her death record from 1831, which states her death location as the farm Hafslund, which is a sub-farm of Fjerdingbye in Rælingen, and which gives her approximate birth year as 1765. This birth year is corroborated by both the 1801 Norwegian census and the entry for Narvestad in the Bygdehistorie for Rælingen. Her 1796 marriage record to Amund Bastiansen (1762-1810) also lists her location as Hafslund. However, I cannot seem to find her birth record nor her parents' names. Does anybody have any suggestions? Here is a link to their marriage record (bottom left corner), and here is a link to her burial record (second from the bottom, on the right). The text of the Bygdehistorie entry for Narvestad is as follows: "Amund Bastiansen 1763-1810 ble neste bruker, han og konen Marie Johannesd. 1765-1832 hadde barna Bastian f. 1796, Johannes f. 1798 til Hestløkka under Nes, Nils f. 1800 til Sørli under Nordby. Amund flyttet senere til Bråten og døde der." There's no further information about them under the Bråten sub-entry.