According to Wally Kairuz, in the novel "Libro de Manuel," Julio Cortazar not only mentions Joni several times, but he also dedicates a poem to her. This book is apparently hard to find, but if you've got it, please let us know about all the Joni mentions. Wally no longer has his copy, but he says that the poem Cortazar wrote begins, "Joni Mitchell, American baby."
This just in: Debra Shea has provided us with this new information:
The following is from "A Manual for Manuel" by Julio Cortazar, published in Argentina in 1973 as "Libro de Manuel", translated from the Spanish by Gregory Rabassa, English translation copyright 1978, pages 356-358. I've typed it out exactly as it's printed, except for these things that I can't do in this plain text message: anything between ** and ** is italicized, the name Falu has an accent over the u, Andres has an accent over the e, Gomez has an accent over the o, and Cortazar has an accent over the first a. I typed out what comes after the end of the poem (which really does end with a comma) only because I love the listing of women, that includes Joni, and the phrase, "their laws on my body." I don't know exactly what that means, but I like it anyway.

When the snails parade
and leave a trail that sketches out the lettuce taste
changing its drivel of delight into the perfume of the full
moon
I am the one who listens in Paris
to Joni Mitchell sing
the one who between two smokes
felt time go by for Pichuco
and Robert Firpo
My grandmother talking to me in a garden in Banfield,
a sleepy suburb of Buenos Aires,
**"Snail, snail
let the sun shine on your tail."**
Maybe that's why on this suburban night
there are snails, Joni Mitchell, American girl,
who sings between two drinks,
between a Falu and a Pedro Maffia
(I haven't got any more time and I don't care for fads,
I mix Jelly Roll Morton and Gardel and Stockhausen,
blessed be the Lamb)
What a strange thing
being Argentine on this night,
knowing I'm going to an appointment
with no one, with a woman who belongs to someone else,
with someone who spoke to me in the dark,
that I'll arrive soon
for what
What a strange thing
being Argentine on this night,
the voice of Joni Mitchell
between a Falu and a Pedro Maffia,
a cocktail of memory, **rare blend of Musetta and Mimi,**
to your health, Delfino, childhood comrade,
being Argentine in a Paris suburb
**"Snail, snail, let the sun shine on your tail."**
Pichuco's concertina, Joni Mitchell,
Maurice Fanon, girl, **me souvenir de toi,
de ta loi sur mon corps,**
being Argentine, walking
to an appointment with whom and for what reason,
such a strange thing
without renouncing Joni Mitchell
being Argentine in this black stain,
Fritz Lang, I am Andres, just tell me,
that house behind the trees,
there certainly, the cedars and the silence,
everything falls together, but then
everything begins to be nothing again,
knowing that I will come to an appointment
with a woman who belongs to someone else,
what a strange thing
("Someone wants to speak to you," a waiter
in a white jacket, the gesture pointing
to the room in the dark)--
I'm coming, my friend,
wait till Joni Mitchell finishes,
till Atahualpa's silent, I'm getting there,
open, Ludmilla, they're waiting for me
in a dark room.
it's a Cuban, the waiter said, he has something
to tell you.
I dreamed all that, of course, and suddenly I remember
precisely on arriving here, the black stain opens,
I see a face, I hear a voice, everything that I dreamed Fritz Lang I remember, like a sheet that's torn in half that garden with cedars in the shadows I remember without surprise, the surprising thing is almost not having recognized it before, from the beginning, on waking up, so clear and obvious and even beautiful to remember it while I approach the door of the chalet and raise my hand so they won't kill me without at least knowing who I am and that I'm not coming to sell them out, what a strange thing being Argentine in this garden and at this hour, plunged into madness and remembering Ludmilla and Francine and Joni Mitchell, their laws on my body, women and voices and bodies and books while I raise my arms so they'll see me easily, Gomez or Lucien Verneuil or maybe Marcos crouching behind the windows, ...

(Contributed by Wally Kairuz, Debra Shea)