Elmajdoub, Aburawi A., and Mary K. Miller. "The 'Eternal Now' in Borges' 'The Garden of Forking Paths' and 'Pierre Menard, Author of Don Quixote' ." Durham University Journal 2 (1991): 249-251.
Good stuff in this article. The concept of the endless present tense and created forms of certainty (ex-calendars) are discussed in full in this short article in relation to Borges' Pierre Menard and The Garden of Forking Paths. Both of these stories are excellent and were used for my senior thesis this past semester. I would have also included a discussion of The Immortal here. When I edit my thesis for online placement I will certainly look at this article again.