diff --git a/src/semra/api.py b/src/semra/api.py
index d0921ba..000c579 100644
--- a/src/semra/api.py
+++ b/src/semra/api.py
@@ -5,7 +5,7 @@
 import itertools as itt
 import logging
 from collections import Counter, defaultdict
-from collections.abc import Callable, Iterable
+from collections.abc import Iterable
 from typing import cast
 
 import networkx as nx
@@ -194,7 +194,8 @@ def infer_chains(
     return [*mappings, *new_mappings]
 
 
-def index_str(index: Index) -> str:
+def tabulate_index(index: Index) -> str:
+    """Tabulate"""
     from tabulate import tabulate
 
     rows: list[tuple[str, str, str, str]] = []
@@ -487,35 +488,6 @@ def validate_mappings(mappings: list[Mapping]) -> None:
             raise ValueError(f"banana in mapping object: {mapping}")
 
 
-def df_to_mappings(
-    df,
-    *,
-    source_prefix: str,
-    target_prefix: str,
-    evidence: Callable[[], Evidence],
-    source_identifier_column: str | None = None,
-    target_identifier_column: str | None = None,
-) -> list[Mapping]:
-    if source_identifier_column is None:
-        source_identifier_column = source_prefix
-    if target_identifier_column is None:
-        target_identifier_column = target_prefix
-    return [
-        Mapping(
-            s=Reference(prefix=source_prefix, identifier=source_id),
-            p=EXACT_MATCH,
-            o=Reference(prefix=target_prefix, identifier=target_id),
-            evidence=[evidence()],
-        )
-        for source_id, target_id in tqdm(
-            df[[source_identifier_column, target_identifier_column]].values,
-            unit="mapping",
-            unit_scale=True,
-            desc=f"Processing {source_prefix}",
-        )
-    ]
-
-
 def summarize_prefixes(mappings: list[Mapping]) -> pd.DataFrame:
     """Get a dataframe summarizing the prefixes appearing in the mappings."""
     import bioregistry
diff --git a/src/semra/sources/ncit.py b/src/semra/sources/ncit.py
index 4aa4389..ec624a5 100644
--- a/src/semra/sources/ncit.py
+++ b/src/semra/sources/ncit.py
@@ -1,13 +1,16 @@
 """Get mappings from NCIT."""
+from __future__ import annotations
 
 from functools import lru_cache
+from typing import Callable
 
 import bioregistry
 import pandas as pd
 import requests
+from curies import Reference
+from tqdm.asyncio import tqdm
 
-from semra import UNSPECIFIED_MAPPING, Mapping, MappingSet, SimpleEvidence
-from semra.api import df_to_mappings
+from semra import EXACT_MATCH, UNSPECIFIED_MAPPING, Evidence, Mapping, MappingSet, SimpleEvidence
 
 __all__ = [
     "get_ncit_hgnc_mappings",
@@ -50,7 +53,7 @@ def _get_evidence() -> SimpleEvidence:
 def get_ncit_hgnc_mappings() -> list[Mapping]:
     df = pd.read_csv(HGNC_MAPPINGS_URL, sep="\t", header=None, names=["ncit", "hgnc"])
     df["hgnc"] = df["hgnc"].map(lambda s: s.removeprefix("HGNC:"))  # type:ignore
-    return df_to_mappings(
+    return _df_to_mappings(
         df,
         source_prefix="ncit",
         target_prefix="hgnc",
@@ -61,7 +64,7 @@ def get_ncit_hgnc_mappings() -> list[Mapping]:
 def get_ncit_go_mappings() -> list[Mapping]:
     df = pd.read_csv(HGNC_MAPPINGS_URL, sep="\t", header=None, names=["go", "ncit"])
     df["go"] = df["go"].map(lambda s: s.removeprefix("GO:"))  # type:ignore
-    return df_to_mappings(
+    return _df_to_mappings(
         df,
         source_prefix="ncit",
         target_prefix="go",
@@ -72,7 +75,7 @@ def get_ncit_go_mappings() -> list[Mapping]:
 def get_ncit_chebi_mappings() -> list[Mapping]:
     df = pd.read_csv(HGNC_MAPPINGS_URL, sep="\t", header=None, names=["ncit", "chebi"])
     df["chebi"] = df["chebi"].map(lambda s: s.removeprefix("CHEBI:"))  # type:ignore
-    return df_to_mappings(
+    return _df_to_mappings(
         df,
         source_prefix="ncit",
         target_prefix="chebi",
@@ -82,7 +85,7 @@ def get_ncit_chebi_mappings() -> list[Mapping]:
 
 def get_ncit_uniprot_mappings() -> list[Mapping]:
     df = pd.read_csv(SWISSPROT_MAPPINGS_URL, sep="\t", header=None, names=["ncit", "uniprot"])
-    return df_to_mappings(
+    return _df_to_mappings(
         df,
         source_prefix="ncit",
         target_prefix="uniprot",
@@ -90,6 +93,35 @@ def get_ncit_uniprot_mappings() -> list[Mapping]:
     )
 
 
+def _df_to_mappings(
+    df,
+    *,
+    source_prefix: str,
+    target_prefix: str,
+    evidence: Callable[[], Evidence],
+    source_identifier_column: str | None = None,
+    target_identifier_column: str | None = None,
+) -> list[Mapping]:
+    if source_identifier_column is None:
+        source_identifier_column = source_prefix
+    if target_identifier_column is None:
+        target_identifier_column = target_prefix
+    return [
+        Mapping(
+            s=Reference(prefix=source_prefix, identifier=source_id),
+            p=EXACT_MATCH,
+            o=Reference(prefix=target_prefix, identifier=target_id),
+            evidence=[evidence()],
+        )
+        for source_id, target_id in tqdm(
+            df[[source_identifier_column, target_identifier_column]].values,
+            unit="mapping",
+            unit_scale=True,
+            desc=f"Processing {source_prefix}",
+        )
+    ]
+
+
 if __name__ == "__main__":
     from semra.api import print_source_target_counts