diff --git a/src/legs.rs b/src/legs.rs
index dd6dd45..9dc91cd 100644
--- a/src/legs.rs
+++ b/src/legs.rs
@@ -42,6 +42,7 @@ impl Leg {
     }
 }
 
+/// Implementation of the definition of landed in [M-4](../methodology.md).
 fn landed(prev_position: &Position, position: &Position) -> bool {
     matches!(
         (&prev_position, &position),
diff --git a/src/trace_month.rs b/src/trace_month.rs
index b05767d..9a8c88e 100644
--- a/src/trace_month.rs
+++ b/src/trace_month.rs
@@ -12,7 +12,7 @@ use crate::{fs, fs_azure};
 
 fn cache_file_path(icao: &str, date: &time::Date) -> String {
     format!(
-        "{DIRECTORY}/{DATABASE}/{}-{}/trace_full_{icao}.json",
+        "{DIRECTORY}/{DATABASE}/{}-{:02}/trace_full_{icao}.json",
         date.year(),
         date.month() as u8
     )