Why no credit to the playwright? Also, differences from the play?

I'm surprised there's no mention in the credits here on imdb of the woman who wrote the play on which this movie was based, Evelyne de la Chevelière. There is even a feature on the DVD dealing with the development of the movie from the play (haven't gotten to watch very much of that feature yet--and it will take me longer to understand it, using my not-so-fabulous French language skills, but it includes scenes from a production of the play, and the playwright is talking to the film's director throughout it). Does anyone know if the actual screen credits give mention of some kind to the playwright? Even if she had no direct involvement in writing the film script, I'd have thought she still would get mention, as is pretty usual these days, when a movie is based on a specific, other work, whether it's a novel, non-fiction book, play, musical, magazine article, blog, or whatever.

I only became interested in seeing this movie after reading glowing reports of an English language production performed this summer, at the Barrington Stage Company, in the Berkshires. I think the play has only one actor, and is apparently very effective. I figured, better to see the movie than nothing, since I couldn't see the play. Does anyone have info about this, as to why imdb makes no mention of the playwright?

Also, if anyone here has seen a production, or read the script of the play, I'd be interested to know what differences and similarities you noted, re. the movie. Thanks.

Added later: I found the playwright is listed on the DVD case credits, I think as "based on a play by." Seems she should be listed on imdb as well.





Multiplex: 100+ shows a day, NONE worth watching. John Sayles' latest: NO distribution. SAD.