fix docs

Author: dakk

docs/source/how_it_works.ipynb

@@ -15,7 +15,7 @@
     "*quantum circuit*.\n",
     "\n",
     "Unlike other libraries that translate individual operations into quantum circuits before combining them, \n",
-    "qlasskit constructs a singular boolean expression for each output qubit of the entire function. \n",
+    "qlasskit constructs a single boolean expression for each output qubit of the entire function. \n",
     "This unique approach facilitates advanced optimization leveraging boolean algebraic properties.\n",
     "\n",
     "\n",

docs/source/index.rst

@@ -34,3 +34,16 @@ Indices and tables
 * :ref:`genindex`
 * :ref:`modindex`
 * :ref:`search`
+
+
+Cite
+======
+
+```
+@software{qlasskit2023,
+  author = {Davide Gessa},
+  title = {qlasskit: a python-to-quantum circuit compiler},
+  url = {https://github.com/dakk/qlasskit},
+  year = {2023},
+}
+```