diff --git a/docs/book/OGZAF_references.bib b/docs/book/OGZAF_references.bib
index 91a992a..3cb3dbf 100755
--- a/docs/book/OGZAF_references.bib
+++ b/docs/book/OGZAF_references.bib
@@ -752,4 +752,19 @@ @Article{LMW2023
   doi={10.1016/j.jimonfin.2022.1},
   abstract={We analyze the long-run impact of sovereign yields on corporate yields of the same country, finding that, for emerging markets, the average pass-through is around one. The pass-through is larger in countries with greater sovereign risk and where sovereign bonds are more liquid. The pass-through is also greater for corporate bonds with lower ratings, shorter maturities, and those issued by financial companies and government-related firms. Our results support theoretical arguments that corporate and sovereign yields are linked together through credit risk and liquidity premiums. Consequently, high sovereign risk can slowdown growth by persistently increasing private sector borrowing costs.},
   url={https://ideas.repec.org/a/eee/jimfin/v130y2023ics0261560622001516.html}
+}
+
+@Article{PRS2020,
+  author={Pain, Julius and Rapapali, Mpho and Steenkamp, Daan},
+  title={{Industry TFP estimates for South Africa}},
+  journal={Occasional Bulletin of Economic Notes},
+  year=2020,
+  volume={},
+  number={},
+  pages={},
+  month={November},
+  keywords={},
+  doi={},
+  abstract={},
+  url={https://econpapers.repec.org/scripts/redir.pf?u=https%3A%2F%2Fwww.resbank.co.za%2Fcontent%2Fdam%2Fsarb%2Fpublications%2Foccasional-bulletin-of-economic-notes%2F2020%2F10412%2FOBEN%25202002%2520%28Industry%2520TFP%2520estimates%2520for%2520South%2520Africa%29%2520-%2520November%25202020.pdf;h=repec:rbz:oboens:10412}
 }
\ No newline at end of file
diff --git a/docs/book/content/calibration/firms.md b/docs/book/content/calibration/firms.md
index a4ef222..8cc5f55 100644
--- a/docs/book/content/calibration/firms.md
+++ b/docs/book/content/calibration/firms.md
@@ -34,4 +34,4 @@ We use a default value of $\gamma =0.40$, which corresponds to one minus labor's
 
 ### Total factor productivity
 
-In the case of the single prodcution sector, we can normalize $Z_{m,t}=1.0$.  In the case of multiple production sectors, we use [Julius Pain, Mpho Rapapali and Daan Steenkamp, "Industry TFP estimates for South Africa", Chapter 5 in Occasional Bulletin of Economic Notes, OBEN/20/02, South African Reserve Bank, Nov. 2020](https://econpapers.repec.org/scripts/redir.pf?u=https%3A%2F%2Fwww.resbank.co.za%2Fcontent%2Fdam%2Fsarb%2Fpublications%2Foccasional-bulletin-of-economic-notes%2F2020%2F10412%2FOBEN%25202002%2520%28Industry%2520TFP%2520estimates%2520for%2520South%2520Africa%29%2520-%2520November%25202020.pdf;h=repec:rbz:oboens:10412) who identify TFP for various sectors in South Africa.
\ No newline at end of file
+In the case of the single prodcution sector, we can normalize $Z_{m,t}=1.0$.  In the case of multiple production sectors, we use {cite}`PRS2020 who identify TFP for various sectors in South Africa.
\ No newline at end of file