diff --git a/src/bng/score.rs b/src/bng/score.rs
index 84ba46c..4aadc1e 100644
--- a/src/bng/score.rs
+++ b/src/bng/score.rs
@@ -33,7 +33,7 @@ pub use de::*;
 
 use super::Expression as Instruction;
 
-#[derive(Deref, From, Default)]
+#[derive(Deref, From)]
 #[cfg_attr(debug_assertions, derive(Serialize, Debug))]
 pub struct Atoms(Vec<Atom>);
 
diff --git a/src/bng/score/de.rs b/src/bng/score/de.rs
index aa97ecd..1745d76 100644
--- a/src/bng/score/de.rs
+++ b/src/bng/score/de.rs
@@ -2,7 +2,7 @@ use derive_new::new;
 use nom::{
     character::complete::one_of,
     combinator::all_consuming,
-    multi::{many0, many1},
+    multi::many0,
     sequence::{preceded, terminated},
     Parser,
 };
@@ -60,12 +60,55 @@ impl<'de> Deserialize<'de> for Atoms {
             notes: String,
             sheet: String,
         }
-        let NotesSheet { notes, sheet } = NotesSheet::deserialize(deserializer)?;
-        if sheet.is_empty() {
-            Ok(Default::default())
-        } else {
-            flat_atom_parser_mapper::<D, _>(&sheet, flat_atom_parser(&notes))
+        struct NotesSheetVisitor;
+        impl<'de> Visitor<'de> for NotesSheetVisitor {
+            type Value = NotesSheet;
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                formatter.write_str("a \"notes\" field and a \"sheet\" field")
+            }
+            fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+            where
+                A: serde::de::SeqAccess<'de>,
+            {
+                let notes = seq
+                    .next_element()?
+                    .ok_or_else(|| de::Error::invalid_length(0, &self))?;
+                let sheet = seq
+                    .next_element()?
+                    .ok_or_else(|| de::Error::invalid_length(1, &self))?;
+                Ok(NotesSheet::new(notes, sheet))
+            }
+            fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
+            where
+                A: de::MapAccess<'de>,
+            {
+                let mut notes = None;
+                let mut sheet = None;
+                while let Some(key) = map.next_key()? {
+                    match key {
+                        Field::Notes => {
+                            if notes.is_some() {
+                                return Err(de::Error::duplicate_field("notes"));
+                            }
+                            notes = Some(map.next_value()?);
+                        }
+                        Field::Sheet => {
+                            if sheet.is_some() {
+                                return Err(de::Error::duplicate_field("sheet"));
+                            }
+                            sheet = Some(map.next_value()?);
+                        }
+                    }
+                }
+                let notes = notes.ok_or_else(|| de::Error::missing_field("notes"))?;
+                let sheet = sheet.ok_or_else(|| de::Error::missing_field("sheet"))?;
+                Ok(NotesSheet::new(notes, sheet))
+            }
         }
+        const FIELDS: &[&str] = &["notes", "sheet"];
+        let NotesSheet { notes, sheet } =
+            deserializer.deserialize_struct("NotesSheet", FIELDS, NotesSheetVisitor)?;
+        flat_atom_parser_mapper::<D, _>(&sheet, flat_atom_parser(&notes))
     }
 }
 
@@ -85,7 +128,7 @@ where
     P: Parser<&'a str, FlatAtom, nom::error::Error<&'a str>>,
 {
     all_consuming(terminated(
-        many1(preceded(maybe_yml_str_space(), parser)),
+        many0(preceded(maybe_yml_str_space(), parser)),
         maybe_yml_str_space(),
     ))(input)
     .map_err(nom_err_message)