22:52 duration 22 minutes 52 seconds
GEB4935 HSA4938 - Lesson 08_ch 6
16:10 duration 16 minutes 10 seconds
GEB4935 HSA4938 - Lesson 07_ch 5
28:34 duration 28 minutes 34 seconds
GEB4935 HSA4938 - Lesson 04_ch 2