Is shmurah matzah really required? What can the Samaritans teach us about who is allowed to produce matzah for the sedarim? What can the requirements for lishma by a get teach us about matzah? Can we use machine shmurah for the sedarim? 
Chullin 3b
Pesachim 40a
Pesachim 38a-b, Rashi sv Ushmartem
Rosh Pesachim 2:26
Rambam, Hilchos Chometz u'Matzah 8:13; 5:8-9
Magid Mishneh ibid. (5:8-9)
Shulchan Aruch OC 453:4
Gittin 23a
Beis Yosef OC 460
Shulchan Aruch OC 460: 1-2
Biur Halacha OC 460: 1-2