Episode ordering

Neither production numbers nor air dates yield a fully coherent ordering of the episodes: "Just Like Old Times" (#79, 06/11/80) must take place after "Play On Love" (#81, 03/03/80) (1), yet also after "Smarts" (#75, 06/18/80) (2). The tie-breaker is that "The Covenant" (#45, 02/21/78) definitely has to come after "And Baby Makes Three" (#46, 02/07/78) (3). Thus the best solution I could think of was to use the air-date ordering, but to move "Smarts" to the beginning of the 5th season, where it clearly belongs. (I'm guessing it got pre-empted, and was shown later instead.)

(1) Jo first appears in "Play On Love," and is mentioned in "Just Like Old Times."
(2) Buddy takes a college aptitude test in "Smarts"; in "Just Like Old Times," she is receiving acceptance letters.
(3) Nancy finds out she's pregnant in "And Baby Makes Three," and miscarries in "The Covenant."