diff --git a/examples/config/phase/mechanical/plastic/phenopowerlaw_Al.yaml b/examples/config/phase/mechanical/plastic/phenopowerlaw_Al.yaml
index 8a0692c9b..5024f99e7 100644
--- a/examples/config/phase/mechanical/plastic/phenopowerlaw_Al.yaml
+++ b/examples/config/phase/mechanical/plastic/phenopowerlaw_Al.yaml
@@ -4,6 +4,9 @@ references:
     Acta Metallurgica 8(3):187-199, 1960,
     https://doi.org/10.1016/0001-6160(60)90127-9,
     fitted from Fig. 5
+  - U.F. Kocks,
+    Metallurgical and Materials Transactions B 1:1121–1143, 1970,
+    https://doi.org/10.1007/BF02900224
 output: [xi_sl, gamma_sl]
 N_sl: [12]
 n_sl: 20
diff --git a/examples/config/phase/mechanical/plastic/phenopowerlaw_Au.yaml b/examples/config/phase/mechanical/plastic/phenopowerlaw_Au.yaml
index b5a034c60..ac9c93ccf 100644
--- a/examples/config/phase/mechanical/plastic/phenopowerlaw_Au.yaml
+++ b/examples/config/phase/mechanical/plastic/phenopowerlaw_Au.yaml
@@ -6,6 +6,9 @@ references:
   - I. Kovács and G.Vörös,
     International Journal of Plasticity 12:35-43, 1996,
     https://doi.org/10.1016/S0749-6419(95)00043-7
+  - U.F. Kocks,
+    Metallurgical and Materials Transactions B 1:1121–1143, 1970,
+    https://doi.org/10.1007/BF02900224
 output: [xi_sl, gamma_sl]
 N_sl: [12]
 n_sl: 83.3
diff --git a/examples/config/phase/mechanical/plastic/phenopowerlaw_Cu.yaml b/examples/config/phase/mechanical/plastic/phenopowerlaw_Cu.yaml
index 23fd38acd..4047703cb 100644
--- a/examples/config/phase/mechanical/plastic/phenopowerlaw_Cu.yaml
+++ b/examples/config/phase/mechanical/plastic/phenopowerlaw_Cu.yaml
@@ -4,6 +4,9 @@ references:
     Transactions of the Japan Institute of Metals 16(10):629-640, 1975,
     https://doi.org/10.2320/matertrans1960.16.629,
     fitted from Fig. 3b
+  - U.F. Kocks,
+    Metallurgical and Materials Transactions B 1:1121–1143, 1970,
+    https://doi.org/10.1007/BF02900224
 output: [xi_sl, gamma_sl]
 N_sl: [12]
 n_sl: 20
diff --git a/examples/config/phase/mechanical/plastic/phenopowerlaw_DP-steel-ferrite.yaml b/examples/config/phase/mechanical/plastic/phenopowerlaw_DP-steel-ferrite.yaml
index 40812c89d..5218e42a8 100644
--- a/examples/config/phase/mechanical/plastic/phenopowerlaw_DP-steel-ferrite.yaml
+++ b/examples/config/phase/mechanical/plastic/phenopowerlaw_DP-steel-ferrite.yaml
@@ -3,6 +3,9 @@ references:
   - C.C. Tasan et al.,
     Acta Materialia 81:386-400, 2014,
     https://doi.org/10.1016/j.actamat.2014.07.071
+  - U.F. Kocks,
+    Metallurgical and Materials Transactions B 1:1121–1143, 1970,
+    https://doi.org/10.1007/BF02900224
 output: [xi_sl, gamma_sl]
 N_sl: [12, 12]
 n_sl: 20