diff --git a/mtg_ssm/serialization/xlsx.py b/mtg_ssm/serialization/xlsx.py
index 4f6ce64..b008628 100644
--- a/mtg_ssm/serialization/xlsx.py
+++ b/mtg_ssm/serialization/xlsx.py
@@ -137,8 +137,8 @@ def get_references(
         set_to_haveref,
         key=lambda setcode: _card_set_sort_key(index.setcode_to_set[setcode]),
     ):
-        reference = 'IF({count}>0,"{setcode}:"&{count},"")'.format(
-            setcode=card_set.upper(), count=set_to_haveref[card_set]
+        reference = (
+            f'IF({set_to_haveref[card_set]}>0,"{card_set.upper()}:"&{set_to_haveref[card_set]},"")'
         )
         references.append(reference)
     if not references:
diff --git a/pyproject.toml b/pyproject.toml
index d6ab7e2..df368b3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -106,6 +106,8 @@ target-version = ["py38"]
 [tool.ruff]
 target-version = "py38"
 line-length = 99
+
+[tool.ruff.lint]
 select = [
     "F",
     "E",
@@ -153,7 +155,7 @@ ignore = [
     "T201", # `print` found; ignoring for now because I don't want to set up logging
 ]
 
-[tool.ruff.per-file-ignores]
+[tool.ruff.lint.per-file-ignores]
 "__init__.py" = [
     "D104", # missing docstring in public package
 ]
@@ -165,9 +167,9 @@ ignore = [
     "S101", # tests should use assert
 ]
 
-[tool.ruff.isort]
+[tool.ruff.lint.isort]
 known-first-party = ["mtg_ssm"]
 
-[tool.ruff.pylint]
+[tool.ruff.lint.pylint]
 max-args = 7
 max-returns = 8