 Central Pennsylvania-based Citizens Northern Corp. plans to gobble up another Bucks County community bank, agreeing to buy Doylestowns Covenant Bank for 77 million. Privately-held Covenant, whose parent company is Covenant Financial, operates two local branches one in Doylestown and another that just opened this year in Paoli. In April, Citizens Northern acquired Doylestowns Monument Bancorp for 43 million. 