B. K. Ahring, Biomethanation, 2003.

D. Deublein and A. Steinhauser, Biogas from Waste and Renewable Resources. An Introduction, 2008.

I. Simeonov, Modelling and Control of the Anaerobic Digestion of Organic Wastes in Continuously Stirred Bioreactors Chapter 2 in: Contemporary Approaches to Modeling, Optimization and Control of Biotechnological Processes, Prof, 2010.

R. Georgiev, K. Peychev, I. Simeonov, and A. , Determination of Minimum Heat Insulation Thickness for an Experimental Methane Fermentor, Agricultural Science and Technology, vol.2, issue.3, pp.160-162, 2010.

I. Simeonov, S. Diop, B. Kalchev, E. Chorukova, and N. Christov, Design of Software Sensors for Unmeasurable Variables of Anaerobic Digestion Processes, th Anniversary of the Stephan Angeloff Institute of Microbiology, pp.307-331, 2012.
URL : https://hal.archives-ouvertes.fr/hal-00828853

I. S. Simeonov, B. L. Kalchev, and N. D. Christov, Parameter and State Estimation of an Anaerobic Digestion Model in Laboratory and Pilot-Scale Conditions, Proc. 18th IFAC World Congress, pp.6224-6229, 2011.
DOI : 10.3182/20110828-6-IT-1002.02542
URL : https://hal.archives-ouvertes.fr/pasteur-00755449

B. Kalchev, N. Christov, and I. Simeonov, Output-feedback H ? Control for a Second-order Nonlinear Model of a Biotechnological Process, Compt. rend. Acad. bulg. Sci, vol.64, issue.1, pp.125-132, 2011.
URL : https://hal.archives-ouvertes.fr/pasteur-00755410

H. Wang, B. Kalchev, I. Simeonov, N. Christov, and C. Vasseur, Composite Adaptive Control for a Simple Biotechnological Process Model, Compt. rend. Acad. bulg. Sci, vol.64, issue.5, pp.737-744, 2011.
URL : https://hal.archives-ouvertes.fr/pasteur-00755415

I. Simeonov and S. Stoyanov, Modelling and Extremum Seeking Control of a Cascade of Two Anaerobic Bioreactors, Int. J. Bioautomation, vol.15, issue.1, pp.13-24, 2011.

I. Simeonov, S. Mihaylova, B. Kalchev, E. Chorukova, and S. Marinova, Study on the Anaerobic Co-digestion of Wasted Fruits and Vegetables, 5 th International Scientific Conference on Water, 2012.

. Assoc and . Prof, Ivan Simeonov, Ph.D. E-mail: issim@microbio.bas

I. Simeonov-was-born-in-dermanci, He graduated from the Technical University of Sofia and specialized in l'Ecole Superieur d'Electricite and Laboratoire de Genie Electrique de Paris, France. He received his Ph.D. degree from the same university in 1981, he has worked in the Bulgarian Academy of Sciences as a researcher and associate professor, 1948.

. Assoc and . Prof, Ivan Simeonov are published in more than 200 scientific articles and 3 monographs with more than 250 citations. Snezhanka Mihaylova E-mail: snejanka11@abv.bg Snezhanka Mihaylova was born in Staro Zhelezare, Bulgaria in 1963. She graduated her higher education from the Agricultural University of Plovdiv, Bulgaria in viticulture and horticulture in 1991. Her scientific interests are in the fields of ecology, floriculture, soil science and plant-growing

. Assoc and . Prof, Anatoliy Aleksandrov

. Assoc and . Prof, Anatoliy Aleksandrov was born in Stara Zagora, Bulgaria in 1958. He graduated his higher education from the Technical University of Gabrovo, Bulgaria. At present Assoc

. Assoc, . Prof, and . Georgiev, He graduated his higher education from the Technical University of Sofia, Bulgaria. Assoc. Prof. Rashko Georgiev specialized in Applied Mathematics at the same University. He worked in a designers' bureau in the field of heating and ventilation. He works now at the Trakia University His scientific interests are in the field of renewable energy sources, heating, ventilation and air conditioning in animal husbandry, 1953.