How many papers were published in the journal "Concepts in Magnetic Resonance Part A"?
journal "Concepts in Magnetic Resonance Part A" refers to FullName = 'Concepts in Magnetic Resonance Part A'
SELECT COUNT(T2.Id) FROM Journal AS T1 INNER JOIN Paper AS T2 ON T1.Id = T2.JournalId WHERE T1.FullName = 'Concepts in Magnetic Resonance Part A'