Jurisprudence on letters testamentary, for administration

The following cases are landmark Supreme Court decisions in cases involving oppositions to the issuances of letters testamentary, petitions for letters of administration and contest for letters of administration.
[1]Sagunsin vs. Lindayag, 6 SCRA 874 (G.R. No. L-17759; December 17, 1962)
[2]San Luis vs. San Luis, G.R. No. 133743, February 6, 2007
[3]De Arranz vs. Galing (G.R. No. 77047; May 28, 1988)
[4]Tayag vs. Tayag-Gallor, G.R. No. 174680, March 24, 2008