http://www.chordie.com/chord.pere/www.ultimate-guitar.com/print.php?what=tab&id=262908

ONE DAY AT A TIME
Artist: Marijohn Wilkins

Words and music: Marijohn Wilkins and Kris Kristofferson

(Words and chords as posted above.)

I also found more info on the copyright, here
http://www.namethathymn.com/hymn-lyrics-detective-forum/index.php?a=vtopic&t=556&p=2

"This song was written by Marijohn Wilkins and Kris Kristofferson. The copyright is held by Buckhorn Music Publishers of which MariJohn Wilkins is the owner. She has written many other songs such as Scars in the Hands of Jesus, I have Returned, His Kind of Love, He Loved Me Enough. She also wrote The Long Black Veil, Waterloo."

(Note: Marijohn Wilkins passed away recently, within the last year, if I recall correctly.)