Dr. Benjamin Shaw makes several significant points about covenantal baptism here. They deserve the most serious consideration by anyone who desires to understand more fully the biblical nature of covenantal signs and seals. I would also recommend that you listen to the audio lectures by Edward Donnelly and Bill Shishko. They are two of the finest defenses from modern theologians. If you want to read more thorough treatments from the annals of church history, I would recommend John Holt Rice's essay on the subject, and the sermon Stephen Marshall preached before the Westminster Assembly.