diff --git a/libfprint/core.c b/libfprint/core.c
index f035c8c..1cb82cc 100644
--- a/libfprint/core.c
+++ b/libfprint/core.c
@@ -248,7 +248,7 @@ static struct fp_dscv_dev *discover_dev(libusb_device *udev)
  * Scans the system and returns a list of discovered devices. This is your
  * entry point into finding a fingerprint reader to operate.
  *
- * Returns: a %NULL-terminated list of discovered devices. Must be freed with
+ * Returns: a nul-terminated list of discovered devices. Must be freed with
  * fp_dscv_devs_free() after use.
  */
 API_EXPORTED struct fp_dscv_dev **fp_discover_devs(void)
diff --git a/libfprint/img.c b/libfprint/img.c
index b0cf976..90f4cd4 100644
--- a/libfprint/img.c
+++ b/libfprint/img.c
@@ -87,7 +87,7 @@ struct fp_img *fpi_img_resize(struct fp_img *img, size_t newsize)
 
 /**
  * fp_img_free:
- * @img: the image to destroy. If NULL, function simply returns.
+ * @img: the image to destroy. If %NULL, function simply returns.
  *
  * Frees an image. Must be called when you are finished working with an image.
  */