If you wish to omit material from within a quotation, indicate the ellipsis by three spaced periods. If a sentence ends in an omission, add a regular period and then three spaced periods to indicate the omission. The following example is based on a quotation from the sentences immediately above this one:

McCarron writes that "if you ...omit material from within a quotation, [you must] indicate the ellipsis.... If a sentence ends in an omission, add a regular period and then three spaced periods...."